15 
© Author(s) 2008. This is an open access article licensed under the Creative Commons 
Attribution-NonCommercial-NoDerivs License (http://creativecommons.org/licenses/
by-nc-nd/4.0/)
	 	 Sodobni	vojaški	izzivi,	oktober	2022	–	24/št.4
	 	 Contemporary	Military	Challenges,	October	2022	–	24/No.	4
Vprašanja o ustrezni in pravični delitvi bremen v zavezništvu so zaveznice že od 
nekdaj razdvajala. V prispevku bodo izpostavljeni različna razumevanja in pristopi 
zaveznic o delitvi bremen v Natu, predvsem razlike med tako imenovanimi vhodnimi 
in izhodnimi merili ter dejstvo, da je zelo težko določiti ustrezno formulo in način 
za pravično delitev bremen držav. Bistvena ugotovitev je, da se še vedno prevelik 
pomen daje doseganju investicijskih parametrov oziroma vhodnih meril, ob tem pa 
so druge oblike prispevkov zaveznic premalo upoštevane. Članek bo zato omejen na 
prikaz zagotavljanja vojaških prispevkov držav kot izhodnih meril, s poudarkom na 
vojaških zmogljivostih za Natove operacije in misije.
Zavezništvo, kolektivna obramba, delitev bremen, mednarodne operacije in misije, 
vojaški prispevek.
Fair burden-sharing within the Alliance has always been a divisive issue and 
disagreements between the allies over this problem have been regular occurrences. 
The paper presents various ways in which the allies approach burden-sharing in 
NATO, stressing the differences between »input« and »output« measures, and the 
fact that it is very difficult to establish an appropriate formula and method for fair 
burden-sharing between the states. Too much emphasis is still being placed on 
»investment parameters« or input measures, while other forms of contributions by 
allies are not given enough weight. The paper focuses on the presentation of national 
military contributions as output.
Alliance, collective defence, burden-sharing, international missions and 
operations, military contribution.
Povzetek
Ključne 
besede
Abstract
Key words
DELITEV VOJAŠKIH BREMEN V ZAVEZNIŠTVU
Špela Boc
MILITARY BURDEN-SHARING 
WITHIN THE ALLIANCE
DOI:10.33179/BSV.99.SVI.11.CMC.24.4.1
 16 Sodobni vojaški izzivi/Contemporary Military Challenges
Špela Boc
The transatlantic security Alliance rests on three pillars: common interests and values, 
political cohesion, and the sharing of the burden for collective defence (Hicks, 2018, 
p 1). When states become members of the Alliance, they also assume the obligation 
to take on equal or fair shares of the burden, one of the key functioning principles 
of the Alliance. Nevertheless, states have different views and positions on how the 
burden-sharing contributions are to be made.
As this paper will demonstrate, discussions and disagreements between the states 
with regard to burden-sharing within the Alliance are not a new phenomenon; they 
seem, however, to have gained prominence in the period before the 2018 NATO 
Summit in Brussels, in particular due to the sharp rhetoric of the former US President, 
Donald Trump1. 
As authors have examined the issue of burden-sharing within alliances and coalitions 
from various theoretical starting points, and carried out research based on a number of 
different variables, the body of literature on this subject is vast and multidisciplinary, 
and the proposed theories offer different levels of analysis. In spite of this, the most 
appropriate burden-sharing method has yet to be found or defined, as every important 
milestone for NATO presents the allies with a new challenge in terms of determining 
the most appropriate and fair method or formula for burden-sharing.
This paper will attempt to demonstrate that the fact which is particularly problematic 
is that the idea of burden-sharing within NATO is mostly centred around financial 
contributions to the joint operation of NATO, i.e. on achieving the »investment 
parameters«2. In contrast, too little attention is given to burden-sharing between 
the states in the form of contributing personnel and material assets to individual 
NATO missions and operations, used by some states as an attempt to compensate 
for not achieving the investment parameters or criteria3, while still trying to present 
themselves as trustworthy and reliable allies. The International Security Assistance 
Force (ISAF) in Afghanistan is the most glaring example of such (disproportionate) 
burden-sharing and, consequently, of all the difficulties arising from the diverse 
interpretations and approaches of states with regard to burden-sharing.
Normally, discussions of the states’ contribution and burden-sharing capacities are 
centred around the question of the extent to which individual states are capable 
or willing to contribute to the »production of public goods«, i.e. to the common 
interests of the Alliance. There is a common belief that wealthier and larger states, 
1 Trump fiercely criticized and attempted to set conditions for the insufficient defence expenditure of the allies, 
even attempting to impose certain ‘sanctionary mechanisms’ on states which did not fulfill their commitments to 
NATO.
2 The proportion of GDP allocated for defence and the proportion of defence expenditure on equipment and 
research and development.
3 While Denmark, for example, failed to achieve any of the defence investment criteria or goals (2% of GDP 
for defence and 20% of the defence budget for main equipment and research and development) in 2015, it 
still ranked high above other states in terms of capabilities and contributions provided to allied operations 
(Mattelaer, 2016, p 29). 
Introduction
 17 Sodobni vojaški izzivi/Contemporary Military Challenges
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
states with high expenditures on defence and their own armed forces, and states 
which are striving to become Alliance members or have done so recently, are more 
likely to contribute their share to the collective efforts of the Alliance.
As they often have fairly limited resources, small states in particular are faced 
with great challenges and pressures concerning their efforts to build adequate and 
trustworthy defence capabilities in the context of the Alliance. In terms of making 
military contributions, NATO missions and operations put a considerable strain on 
such states. Their capacities to contribute to such missions are therefore either limited 
to carrying out support functions and tasks, or they compensate for the capabilities 
they lack by making non-resource-consuming contributions4 (Männik, 2004).
Instead of merely presenting the traditional, i.e. investment criteria for burden-
sharing, this paper aims to present other forms of burden-sharing, or »security 
benefits«, which can also be contributed to the Alliance by the states. To this end, 
the research is centred around that aspect of burden-sharing which concerns military 
contributions to NATO missions and operations, placing emphasis on presenting 
the burden-sharing policy and the states’ military contributions in the largest NATO 
operation to date, the ISAF. In addition, the paper will attempt to demonstrate 
whether the most appropriate and fair method or formula for burden-sharing within 
the Alliance actually exists.
 1 BURDEN-SHARING WITHIN AN ALLIANCE
Burden-sharing is the art of manipulating relationships between allies for political 
gain (Ringsmose, 2010, p 321). This is why, at the time of NATO’s founding, Article 
3 of the North Atlantic Treaty5 was designed to prevent the problem of allied burden-
sharing in advance, stating the provisions and obligations of Member States in 
building their own defence capabilities and contributing to collective defence.
Nevertheless, as Becker notes, »‘burden-sharing’ has been an issue for NATO 
since its birth« (Becker, 2017). The various discussions of burden-sharing6 within 
the Alliance are as old as the Alliance itself (Zycher, 1990, p 1). In particular, 
burden-sharing tends to gain additional prominence during transitional phases of 
the Alliance. Events such as organizational reforms, enlargement, major changes in 
dominant military strategic thinking (for example shifting emphasis on conventional 
vs. nuclear weapons in defence policy), or new out-of-area operations, have often led 
4 For example, by allowing their territory or infrastructure to be used by the Alliance.
5 »In order more effectively to achieve the objectives of this Treaty, the Parties, separately and jointly, by means 
of continuous and effective self-help and mutual aid, will maintain and develop their individual and collective 
capacity to resist armed attack« (NATO, 2019).
6 Discussions of burden-sharing within NATO took place in various disciplines: economics, international 
political economics and international relations. Each of these disciplines claimed to provide the best theory for 
studying the various behaviours of states when it came to burden-sharing (Zyla, 2016, p 5). 
 18 Sodobni vojaški izzivi/Contemporary Military Challenges
to intra-Alliance debate on how the new costs or additional responsibilities should be 
divided (Koivula, 2021, p 146).
Since the early 1990s, four relatively recurring and potentially simultaneous turning 
points have been observed within NATO when the issue of burden-sharing became a 
source of political disputes between the Member States. These four factors or triggers 
– geopolitical changes in connection with Russia, major out-of-area operations, the 
withdrawal or return of the US, and European passivity or activism – did not occur 
sequentially or in a particular order, but at times appeared simultaneously within the 
political space. Thus, NATO has often faced both such disputes and their triggering 
factors at the same time (Koivula, 2021, p 154).
Cyclic 
driver
Russian 
contraction or 
expansion
NATO/allied 
military 
operations
US retrenchment or 
renewal
European passivity or 
activism
Examples Collapse of the 
Soviet Union
NATO operation 
Kosovo
A contest between 
competing US interests 
to share more of the cost 
of transatlantic security 
without ceding US 
leadership
European (strategic 
culture of) defence 
under-spending
NATO 
enlargements, in 
particular in 1999
NATO operation 
Libya
US »pivot to Asia«; US 
Asia-first strategy
Disparities in NATO 
member’s willingness 
to take risks in NATO 
operations
Occupation of 
Crimea
NATO operation 
Afghanistan
America’s disregard of 
Europe’s policy priorities
The emergence and 
development of the EU 
Common Security and 
Defence Policy
Exposure by 
Russia of Eastern 
NATO members 
and partners (e.g. 
Georgia)
US-led 
intervention in 
Iraq 1990-91 
and 2003
The increased difficulty in 
sustaining NATO’s »value 
narrative« during the 
Trump Administration 
The relative weight of 
military vs. non-military 
contributions to collective 
security
In recent years, »revisionist efforts« aimed at altering the interpretations and 
understanding of burden-sharing seem to have gained importance. In particular, the 
period of expeditionary operations, or operations outside the territories of NATO 
Member States, represented a turning point, when it became evident that the burden-
sharing measures and criteria originating from the Cold War period were no longer 
appropriate and sufficient, and that they were not always fair.
Given the rapid increase in the number of operations outside the territories of Member 
States, researchers began to study the states’ contributions to specific missions, 
Table 1: 
Cyclic drivers of 
post-Cold War 
NATO burden-
sharing disputes
(Source: Carry 
That Weight: 
Assessing 
Continuity 
and Change in 
NATO’s Burden-
Sharing Disputes 
(Koivula, 2021, 
p 155).)
Špela Boc
 19 Sodobni vojaški izzivi/Contemporary Military Challenges
to intra-Alliance debate on how the new costs or additional responsibilities should be 
divided (Koivula, 2021, p 146).
Since the early 1990s, four relatively recurring and potentially simultaneous turning 
points have been observed within NATO when the issue of burden-sharing became a 
source of political disputes between the Member States. These four factors or triggers 
– geopolitical changes in connection with Russia, major out-of-area operations, the 
withdrawal or return of the US, and European passivity or activism – did not occur 
sequentially or in a particular order, but at times appeared simultaneously within the 
political space. Thus, NATO has often faced both such disputes and their triggering 
factors at the same time (Koivula, 2021, p 154).
Cyclic 
driver
Russian 
contraction or 
expansion
NATO/allied 
military 
operations
US retrenchment or 
renewal
European passivity or 
activism
Examples Collapse of the 
Soviet Union
NATO operation 
Kosovo
A contest between 
competing US interests 
to share more of the cost 
of transatlantic security 
without ceding US 
leadership
European (strategic 
culture of) defence 
under-spending
NATO 
enlargements, in 
particular in 1999
NATO operation 
Libya
US »pivot to Asia«; US 
Asia-first strategy
Disparities in NATO 
member’s willingness 
to take risks in NATO 
operations
Occupation of 
Crimea
NATO operation 
Afghanistan
America’s disregard of 
Europe’s policy priorities
The emergence and 
development of the EU 
Common Security and 
Defence Policy
Exposure by 
Russia of Eastern 
NATO members 
and partners (e.g. 
Georgia)
US-led 
intervention in 
Iraq 1990-91 
and 2003
The increased difficulty in 
sustaining NATO’s »value 
narrative« during the 
Trump Administration 
The relative weight of 
military vs. non-military 
contributions to collective 
security
In recent years, »revisionist efforts« aimed at altering the interpretations and 
understanding of burden-sharing seem to have gained importance. In particular, the 
period of expeditionary operations, or operations outside the territories of NATO 
Member States, represented a turning point, when it became evident that the burden-
sharing measures and criteria originating from the Cold War period were no longer 
appropriate and sufficient, and that they were not always fair.
Given the rapid increase in the number of operations outside the territories of Member 
States, researchers began to study the states’ contributions to specific missions, 
causing a shift in the discussions of burden-sharing. The issues which became 
important were how and why states made their contributions to specific missions, as 
well as the issue of measuring the performance of states in crisis-response operations 
within NATO crisis management (Bogers, 2019, p 19). 
Another turning point came after 2014, when NATO’s purpose of providing 
collective defence became (more) central once again, this time particularly in the 
form of burden-sharing actions as a way of providing assistance to Member States 
and adjusting the military posture of the Alliance. These actions have mostly been 
centred on expanding the infrastructure to support the strengthening of Member 
States’ forces and, in particular, improving their readiness (US budget 2023, 2022).
 1.1  The definition of burden-sharing 
The most widely used starting theory to understand the concept of burden-sharing is 
Olson’s theory of collective action, which is based on his book, the Logic of Collective 
Action. Drawing from Olson’s theory, Hillison states that a unified definition of the 
term »burden-sharing« describes it as the distribution of costs and risks among the 
members of a group striving to achieve a common goal (Hillison, 2014).
The theory proposed by Olson describes methods of providing »public goods«7, 
i.e. the participation of states in collective action, positing that Alliance members 
contribute to the collective provision of public goods according to their relative power, 
as well as private incentives and motives. According to this theory, superpowers 
shoulder the largest share of the collective burden, while smaller and weaker states 
contribute a marginal share of public goods, gaining undeserved benefits at the 
expense of large (super)powers. In doing so, smaller states supposedly rely on the 
idea that public goods will be provided by larger states in any case, without the need 
for small states to contribute anything. In general, this relationship is supposedly 
about smaller Member States taking advantage of larger Member States, which make 
disproportionately greater contributions while being exploited by smaller states, 
exhibiting a behaviour referred to as »free-riding« (Hillison, 2014).
Authors who have delved deep into the issues of burdens include Hartley and 
Sandler, and Forster and Cimbala. Hartley and Sandler (1999, p 669) stated that 
burden-sharing is usually defined in terms of the actual contribution of each state to 
collective defence, and in terms of the fairness of such a contribution. Forster and 
Cimbala (2005, p 1), on the other hand, define burden-sharing as the division of costs 
and risks among the members of a group in the pursuit of a common goal. Risks can 
be political, military or of other types.
In his research on the behaviour of small states which joined NATO during the 
enlargement process in the late 1990s and early 2000s and then began contributing 
to the ISAF, Hillison studied whether the small states were the recipients or suppliers 
7 In this case, the relevant public good is safety. 
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
 20 Sodobni vojaški izzivi/Contemporary Military Challenges
of security. Examining their contributions and activities within the Alliance in the 
context of burden-sharing, he defined the responsibility for burden-sharing as 
»the distribution of costs and risks among members of a group in the process of 
accomplishing a common goal«, and carried out his research within the framework 
of the theory of collective action. He described states which did not contribute to 
the implementation or achievement of a collective goal as states which exploit the 
power or engagement of other states for their own interests (the »free-riding« states) 
(Hillison, 2009, p v). 
Cooper and Zycher (1989, pp v-vi) stressed that the incessant disagreements over 
burden-sharing within NATO originate from the different interests and interpretations 
concerning the goals, resources, costs and benefits of activities carried out collectively 
by NATO. This is why no detailed burden-sharing formula has been devised in 
NATO, and it is unlikely that such a formula would be accepted either in principle 
or in practice; in addition, NATO itself has refused to establish a detailed burden-
sharing regime for its members (Cooper, Zycher, 1989, p 6). Throughout various 
periods, it turned out that efforts to form a more binding and appropriate formula 
or method for burden-sharing among the allies were particularly dependent on the 
processes and activities taking place at the level of the Alliance in individual periods, 
and on political pressures from the most important allies.
 1.2  The definition of a military contribution 
While a number of definitions of burden-sharing can be found in the literature, this 
does not hold true for definitions of military contributions. Based on a review of 
the available literature, it has been established that there is no generally accepted 
definition of the term »military contribution«. Thus, the concept is most easily and 
accurately defined by attempting to explain it in terms of the forms in which it occurs. 
In the most general sense, military contributions involve the provision of military 
support in accordance with international law, without endangering the security of 
the civilian population, and with the aim of fulfilling specific commitments and 
obligations adopted in the context of specific security organizations. 
In the most general sense, the provision of military contributions represents a state’s 
military-level response, i.e. the response of the military component of a state within 
the framework of collective action, for the purpose of participation and burden-
sharing in allied or coalition missions and operations. It occurs in various forms and 
ways, as it can entail:
 – The provision of military assistance (deploying armed forces members to the state 
of intervention in order to engage in capacity building);
 – The assumption of certain obligations in counteracting threats in the state where 
the intervention takes place (combat and non-combat activities or operations); 
 – The provision of various types of (air, naval, land) transport capabilities in crisis 
areas or in the rear area;
Špela Boc
 21 Sodobni vojaški izzivi/Contemporary Military Challenges
 – Assistance in terms of military equipment and weapons or defence supplies 
(ammunition etc.); 
 – The provision of military personnel in order to fill various posts within missions 
and operations or other military activities. 
A common characteristic of military contributions is that they involve forces and 
resources which are usually intended for stabilizing crisis areas or maintaining peace 
and security; military assistance in the reconstruction of a state and its institutions; 
or, recently, the performance of NATO peacetime activities in the form of a 
comprehensive and credible deterrence and defence posture of the Alliance. 
Zycher, meanwhile, points out that with regard to military contributions in allied 
operations, it is important that the contributions made by an individual state also 
benefit other Member States. Goods or contributions which are purely private in 
nature, i.e. those which only benefit the state which provides them, should not count 
as contributions to the Alliance as a whole (Zycher,1990, p vi).
 2 BURDEN-SHARING MEASURES AND CRITERIA
A thousand different ways exist for evaluating Alliance burden-sharing. This has not 
only to do with methodology, but also with the tendency in all nations to discount the 
value of the efforts undertaken by others (Mattelaer, 2016, p 26). Authors who have 
addressed the issue of burden-sharing and the relevant measures and criteria have 
done so in various ways. Some have attempted to present and explain burden-sharing 
by developing various mathematical formulas or numerical definitions in order to 
measure contributions, resulting in several mathematical models of burden-sharing 
within alliances. Others have worked on more descriptive definitions, rejecting 
the numerical ones as too complex, insufficient and unable to provide credible or 
fair results. In addition, some authors (Sperling and Webber, 2009, Becker and 
Malesky, 2017) have studied burden-sharing predominantly in the context of making 
contributions (money, equipment, armaments, personnel) to NATO missions and 
operations.
Despite all this, NATO eventually had to formulate certain measures and criteria 
for contributions made by states in the context of burden-sharing. The level of 
defence expenditure corresponding to the proportion of gross domestic product 
(GDP) allocated for defence was established as the original quantitative criterion or 
measure, even though there were concerns about its deficiency (Hartley and Sandler, 
in Pavlíčková and Bartoszewicz, 2020, p 338). 
Since the 1960s, scholars have used military expenditure as the key measure of a 
member’s willingness to contribute to the NATO Alliance – sometimes using total 
military expenditure, sometimes disaggregating expenditure on military research 
and development, sometimes dividing military expenditure by the state’s population, 
and so forth (Cooper, Stiles, 2021, p 2). After the end of the Cold War, when NATO 
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
 22 Sodobni vojaški izzivi/Contemporary Military Challenges
underwent a transformation and was becoming increasingly involved in global 
affairs – particularly by participating in missions outside the territories of NATO 
members8 – other types of contributions, such as the sustainability and deployability 
of defence capabilities, began to be taken into account as well (Hartley and Sandler, 
in Pavlíčková and Bartoszewicz, 2020, p 338). 
Becker states that in the sense of collective security, and collective defence in 
particular, NATO views burden-sharing as the extent to which individual members 
mobilize their national resources for the purpose of common priority tasks. In practice, 
this means defence expenditure, and Becker describes the publicly available defence 
expenditure data as a consistent basis for comparing the defence efforts of Alliance 
members based on the common definition of defence expenditure (Becker, 2017). 
Further, Becker states that in order to facilitate the comparison, defence expenditure 
data can be broken down into personnel, equipment, miscellaneous (operating and 
maintenance) and infrastructure. Becker demonstrated the applicability of operating 
and maintenance expenditures as an adequate approximation of the operational 
burden-sharing in out-of-area operations conducted by NATO (Becker, 2017). While 
discussions in the period before NATO began to conduct such operations were mostly 
focused on how much expenditure was allocated to armed forces (the military), this 
later period has seen the focus shift to the issue of whether the Alliance members are 
capable of contributing to out-of-area operations. This brought to the fore debates 
on the methods of measuring the various contributions of Member States to these 
operations. Ringsmose points out that NATO accordingly adopted a set of new 
criteria for analyzing burden-sharing (Ringsmose, 2010).
So far, discussions and research concerning this issue have demonstrated that 
the greatest challenge, as Becker observes, is to »operationalize the ‘form of 
contribution’« (Becker, 2017).
  Wales 2014 – Defence Investment Pledge (DIP)
The 2% defence expenditure threshold, which was not officially confirmed until 
the 2014 NATO Summit in Wales, had been recognized as an unofficial measure of 
the defence expenditure or spending of NATO members for more than a decade9. 
In 201410, the 2% expenditure share became the main method of measuring the 
contributions of NATO members to the Alliance (Hicks, 2018). It became known 
as the long-term Defence Investment Pledge, involving two quantitative input 
measures or figures which determine how much each ally must spend on defence, 
and nine output measures (Bell, 2022, p 2); in total, the DIP therefore encompasses 
11 measures. 
8 Referred to as »out-of-area« missions and operations.
9 At the 2002 NATO Summit in Prague, Member States reached a »gentlemen’s agreement« to reach a 2% defence 
expenditure threshold (Hicks, 2018). 
10 In response to Russia’s unlawful annexation of Crimea and the military intervention in the eastern region of 
Donbas in Ukraine (Bell, 2022, p 2).
4.0
3.
76
3.
47
2.
42
2.
36
2.
34
2.
12
2.
10
2.
03
2.
00
1.
99
1.
90
1.
78
1.
75
1.
67
1.
65
1.
62
1.
55
1.
55
1.
54
1.
44
1.
44
1.
39
1.
33
1.
27
1.
22
1.
22
1.
18
1.
01
0.
58
Gr
ee
ce
Un
ite
d S
tat
es
Po
lan
d
Lit
hu
an
ia
Es
to
nia
Un
ite
d K
ing
do
m
La
tvi
a
Cr
oa
tia
Slo
va
k R
ep
ub
lic
Ro
m
an
ia
Fra
nc
e
No
rth
 M
ac
ed
on
ia
M
on
ten
eg
ro
Bu
lga
ria
Ne
th
erl
an
ds
Al
ba
nia
No
rw
ay
Hu
ng
ary Ita
ly
Ge
rm
an
y
Po
rtu
ga
l
De
nm
ark
Cz
ec
h R
ep
ub
lic
Ca
na
da
Slo
ve
nia
Tu
rke
y
Be
lgi
um
Sp
ain
Lu
xe
m
bo
ur
g
NATO guideline 2%
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
52
.4
0
48
.0
0
45
.3
0
31
.6
0
31
.1
0
30
.8
0
30
.5
0
30
.5
0
29
.9
0
28
.6
0
28
.1
0
27
.2
0
26
.3
0
26
.2
0
26
.0
0
25
.0
0
24
.6
0
23
.7
0
22
.7
0
22
.6
0
21
.6
0
20
.9
0
20
.4
0
20
.0
0
19
.3
0
19
.2
0
18
.7
0
17
.9
0
17
.9
0
Lu
xe
m
bo
ur
g
Hu
ng
ary
Gr
ee
ce
No
rw
ay
No
rth
 M
ac
ed
on
ia
Tu
rke
y
Lit
hu
an
ia
Cr
oa
tia
De
nm
ark
Fra
nc
e
Un
ite
d K
ing
do
m
Un
ite
d S
tat
es
Slo
va
kia
Sp
ain
Ro
m
an
ia
M
on
ten
eg
ro
La
tvi
a
Ne
th
erl
an
ds Ita
ly
Bu
lga
ria
Es
to
nia
Ge
rm
an
y
Po
lan
d
Al
ba
nia
Be
lgi
um
Cz
ec
h R
ep
ub
lic
Ca
na
da
Po
rtu
ga
l
Slo
ve
nia
NATO guideline 20%
60
%
50
40
30
20
10
0
Špela Boc
 23 Sodobni vojaški izzivi/Contemporary Military Challenges
4.0
3.
76
3.
47
2.
42
2.
36
2.
34
2.
12
2.
10
2.
03
2.
00
1.
99
1.
90
1.
78
1.
75
1.
67
1.
65
1.
62
1.
55
1.
55
1.
54
1.
44
1.
44
1.
39
1.
33
1.
27
1.
22
1.
22
1.
18
1.
01
0.
58
Gr
ee
ce
Un
ite
d S
tat
es
Po
lan
d
Lit
hu
an
ia
Es
to
nia
Un
ite
d K
ing
do
m
La
tvi
a
Cr
oa
tia
Slo
va
k R
ep
ub
lic
Ro
m
an
ia
Fra
nc
e
No
rth
 M
ac
ed
on
ia
M
on
ten
eg
ro
Bu
lga
ria
Ne
th
erl
an
ds
Al
ba
nia
No
rw
ay
Hu
ng
ary Ita
ly
Ge
rm
an
y
Po
rtu
ga
l
De
nm
ark
Cz
ec
h R
ep
ub
lic
Ca
na
da
Slo
ve
nia
Tu
rke
y
Be
lgi
um
Sp
ain
Lu
xe
m
bo
ur
g
NATO guideline 2%
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
52
.4
0
48
.0
0
45
.3
0
31
.6
0
31
.1
0
30
.8
0
30
.5
0
30
.5
0
29
.9
0
28
.6
0
28
.1
0
27
.2
0
26
.3
0
26
.2
0
26
.0
0
25
.0
0
24
.6
0
23
.7
0
22
.7
0
22
.6
0
21
.6
0
20
.9
0
20
.4
0
20
.0
0
19
.3
0
19
.2
0
18
.7
0
17
.9
0
17
.9
0
Lu
xe
m
bo
ur
g
Hu
ng
ary
Gr
ee
ce
No
rw
ay
No
rth
 M
ac
ed
on
ia
Tu
rke
y
Lit
hu
an
ia
Cr
oa
tia
De
nm
ark
Fra
nc
e
Un
ite
d K
ing
do
m
Un
ite
d S
tat
es
Slo
va
kia
Sp
ain
Ro
m
an
ia
M
on
ten
eg
ro
La
tvi
a
Ne
th
erl
an
ds Ita
ly
Bu
lga
ria
Es
to
nia
Ge
rm
an
y
Po
lan
d
Al
ba
nia
Be
lgi
um
Cz
ec
h R
ep
ub
lic
Ca
na
da
Po
rtu
ga
l
Slo
ve
nia
NATO guideline 20%
60
%
50
40
30
20
10
0
Chart 1: 
Defence 
expenditure of 
NATO countries 
as a share of 
GDP (%) 2022 
(estimates)
(Source: Defence 
Expenditure of 
NATO States 
2014-2022 
(NATO, 2022a, 
p 3)
Chart 2: 
Weapons and 
equipment 
expenditure as a 
share of defence 
expenditure (%) 
2022 (estimates)
(Source: Defence 
Expenditure of 
NATO States 
2014-2022 
(NATO, 2022a, 
p 3)
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
 24 Sodobni vojaški izzivi/Contemporary Military Challenges
The two input measures (2% of GDP on defence expenditure and 20% of defence 
expenditure on capability development) became the reference criteria for measuring 
and comparing the performance of the Alliance members, as reflected in the NATO 
Secretary General’s Annual Report (Bell, 2022, p 2). In the general sense, these 
two input measures are also understood as investment parameters. The remaining 
nine output measures indicate the effectiveness of each state in using its defence 
resources. These measures include: 1. The percentage of air, land, and naval forces 
that are deployable; 2. The percentage of deployable air, land, and naval forces that 
can be sustained in deployment; 3. The percentage of Capability Targets allocated 
to that ally in accordance with the NATO Defence Planning Process (NDPP) that 
have been met; 4. The percentage of deployable air, land and naval forces deployed 
on NATO Operations and Missions abroad; 5. The percentage of deployable air, 
land, and naval forces deployed on non-NATO Operations and Missions abroad; 
6. The percentage of deployable air, land, and naval forces deployed in support of 
NATO Assurance Missions; 7. The percentage of billets within the NATO Command 
Structure assigned to that ally that have been filled; 8. The percentage of billets 
within the NATO Force Structure Headquarters assigned to that ally that have been 
filled; and 9. The contribution by that ally to the Immediate Response Force (IRF) of 
the NATO Response Force (NRF) (Bell, 2022, p 2).
It is essential that these nine output measures involve military capabilities which 
are monitored by NATO planners and are assessed, and which reflect the actual 
contributions in the form of land forces, aircraft and vessels deployed on operations, 
and in the form of NATO missions and operations personnel and personnel assigned 
to posts within individual NATO structures. 
Following the decision to adopt the nine output measures, the problems of such 
an open or public presentation of burden-sharing did not become evident until it 
was put into practice. Most allies actually refused to make their reports on the nine 
output measures public, so the national data sent to NATO had to remain classified. 
This means that the only DIP data which is released to the public each year merely 
concerns the achievement of the (2% and 20%) investment parameters (Bell, 2022), 
which is why the DIP is mostly treated as synonymous with these two quantitative 
metrics, while the other nine are neglected.
  Stoltenberg’s triple C
In 2017, prior to the NATO Summit in Brussels, and following numerous discussions 
within NATO and increasing objections by the US with regard to the European 
allies bearing too small a share of the burden and not achieving the 2% of the GDP 
for defence criterion, the NATO Secretary General, Jens Stoltenberg, expanded 
the definition of burden-sharing to include not only »financial resources« but also 
Member State »capabilities and obligations« (Binnendijk, 2018). This period was 
seen as a revival of the discussions of burden-sharing within NATO, triggered, for 
the most part, by the then US President Donald Trump. 
Špela Boc
 25 Sodobni vojaški izzivi/Contemporary Military Challenges
Stoltenberg wanted to imply that burden-sharing was not just about expenditure, 
which led to the implementation of the burden-sharing principle according to the 
three Cs: burden-sharing was to be measured in cash, capabilities and contributions 
to NATO missions (Žerjavič, 2017). For each of these three categories, NATO has 
agreed to formal mechanisms that allow allies to monitor, measure and, if appropriate, 
challenge each ally’s performance (Bell, 2022, p 4). 
  NATO Defence Planning Process – fair burden-sharing
The purpose of a defence planning process is to coordinate capability planning, 
i.e. to convert defence expenditure into intermediate defence inputs which, as 
agreed by the states, represent priority tasks11 (Becker, 2017). Arising as part of the 
requirement apportionment and target-setting phase (Step 3) of the Nato Defence 
Planning Process (NDPP) is the principle of fair burden-sharing, i.e. of taking on a 
proportional share, whereby (fair) burden-sharing is based on the evaluation of the 
national GDP in relation to the total Minimum Capability Requirement (MCR12), 
rather than on the evaluation of defence expenditure. 
Within this step, the Minimum Capability Requirements are divided up among the 
individual Member States and NATO entities (such as agencies) in the form of »target 
packages«, taking into account the principles of fair burden-sharing and reasonable 
challenge (Ržen, 2013, p 48). The aim of this process, known as apportionment, is to 
implement these principles (NATO document, 2017).
According to findings by Ringsmose, »in parallel with NATO’s transformation from 
a provider of defence and deterrence to an exporter of stability, the alliance has 
adopted a range of new measures of contribution«. The traditional input indicators 
– particularly defence expenditure as a share of national output – still serve as 
important indicators, but as the Alliance has developed from »an alliance in being« 
into »an alliance in doing«, other measures of contributions have gained prominence. 
According to the author, output measures are gaining prominence over the financial 
criteria of contribution, meaning that the assessment of contributions to joint NATO 
efforts made by individual states uses a greater number of measures than before 
(Ringsmose, 2010, p 326).
Hartley and Sandler express the opinion that states can contribute to the Alliance 
in various ways, either based on the benefits received or based on their capacity to 
make proportional or gradual payments. In the most general sense, contributions 
which can be provided or contributed to the Alliance by the states are defined by:
11 The NDPP aims to coordinate capability planning – in other words the conversion of defence spending into 
intermediate defence outputs that states agree are priorities (Becker, 2017).
12 NATO determines its »Minimum Capability Requirement« through a structured process, based on »Political 
Guidance« agreed by the Nations. Among other things, this guidance incorporates the number, scale and nature 
of the operations which NATO should be able to conduct, referred to as the Alliance’s »Level of Ambition« 
(NATO document, 2017).
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
 26 Sodobni vojaški izzivi/Contemporary Military Challenges
 – »Input measures«: defence expenditure;
 – »Output measures«: deployable forces, military contributions;
 – »Risk-sharing measures«: national caveats, the number of casualties (Hartley and 
Sandler, in Bogers et al., 2020, p 5).
 3 BURDEN-SHARING IN THE CONTEXT OF SECURITY 
MULTILATERALISM
Multilateral security structures are tools which function according to the will of 
the Member States, relative to their political and military commitment (Rotfeld, 
1994). First and foremost, multilateralism is a way of sharing the physical burdens 
of an intervention during the combat phase and, in particular, in the subsequent 
reconstruction operations after the combat ceases (Kreps, 2007, p 66). 
While most of the earlier literature on burden-sharing focused on general burden-
sharing within the Alliance, more and more researchers began to examine burden-
sharing in ad hoc coalitions and in multinational conflict prevention and crisis 
management operations (Ashraf, 2011, p 21).
To a large extent, multinational military operations prevent an individual armed 
forces overstraining from the perspective of shouldering burdens and carrying out 
too wide a range of activities. Multinational military operations allow the burdens 
to be shared between the military contingents of several contributing states. 
Regardless of the end of the military activity spectrum on which these operations are 
conducted, the main purpose and advantage of carrying out multinational activities 
is the faster achievement of common goals by way of operational burden-sharing 
between Member States, in conjunction with minimal financial costs and casualties. 
In addition to decreasing costs, joint operations also significantly increase combat 
power (Kingsley, 2014, p 17). 
Commitments to international operations provide an excellent opportunity for states 
to demonstrate their trustworthiness as future NATO members (Paljak, in Molder, 
2014, p 64). By participating in NATO operations and missions, the states striving 
for NATO membership, in particular, attempt to present themselves as suppliers, 
rather than mere consumers, of security. Through military contributions, these states 
attempt to create an impression of trustworthiness and being loyal allies or partners.
As suggested by Molder, the participation of combat units in international military 
operations depends on the political consensus, human resources and assets. In this 
context, limited resources sometimes limit the military capabilities which can be 
offered by a state for the purpose of international cooperation, even though there 
is the political will or backing for such cooperation (Molder, 2014, p 68). Thus, 
states with limited financial and material resources are unable to carry out missions 
independently, which forces them to liaise and cooperate with other states, particularly 
when carrying out extensive or riskier tasks. 
Špela Boc
 27 Sodobni vojaški izzivi/Contemporary Military Challenges
When a unanimous decision to participate in a mission or operation is made 
within the Alliance at the level of the North Atlantic Council (NAC), states decide 
for themselves whether they will make contributions, except in the context of a 
collective defence operation under Article 5 of the North Atlantic Treaty. Since 
NATO, as an organization, does not have its own armed forces, individual states 
need to contribute their own troops and equipment. Both originate from the states’ 
own defence capabilities, while states also need to pay the deployment costs of 
troops and equipment themselves (NATO, 2022b). The actual military contributions 
to NATO missions and operations only occur after preliminary policy discussions 
and decision-making at the political and military levels. At the NATO level, states 
coordinate contributions among themselves at force generation conferences. 
The process related to the contributions made by states to international operations 
is part of the operational planning of individual states. Operational planning13 deals 
with the planning and deployment of armed forces in potential operations according 
to the current or future security environment and the associated planning situations, 
and is carried out at the strategic, operational and tactical levels. Operational 
planning consists of a package or set of operational plans which should include the 
entire spectrum of mission-related tasks. In order to be able to carry out the whole 
range of roles and tasks of the armed forces, both the Alliance and individual allied 
states must devise an operational planning system comprising advanced planning 
and contingency planning (Hudhra, 2018, p 14).
For states, contributions to military operations result in various burdens as the 
sustainment of troops and equipment in the area of operations can put a strain on 
defence budgets, particularly those of small countries. In addition, the political risks 
of such contributions, arising from the participation of troops in military operations 
in distant areas, should not be underestimated (Forster and Cimbala 2005, p 22). 
Military operations involving several states can cause attempts at cheap cooperation 
or even free-riding, as predicted by the theory of collective action. 
Kavanagh et al. (2021, pp 37-38) see burden-sharing in operations as the sharing 
of the operational burdens (personnel, resources) or the costs of all the activities 
carried out as part of a mission. Coalition partners may provide financial resources, 
personnel and equipment for direct participation in combat or other operations, or 
support which is not directly related to warfare (such as military medical units or 
other forms of assistance). 
Cooper and Stiles (2021, p 1) state that in post Cold War NATO, the number of troops 
(relative to the population) deployed to operations outside the territories of NATO 
Member States has been one of the strongest measures of national commitment to 
the Alliance. In spite of this, expeditionary operations, or operations outside the 
territories of the Alliance Member States, have so far demonstrated that the sharing 
13 In terms of hierarchy, operational planning is part of defence planning, which includes (in addition to 
operational planning) force planning and many other aspects (Hudhra, 2018, p 18).
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
 28 Sodobni vojaški izzivi/Contemporary Military Challenges
of the burden between the Member States is often very disproportionate, and mostly 
dependent on the gains and interests pursued by individual countries.
Although the size of the contingent and the financial contributions of a state to 
the mission have been the most widely used indicators of burden-sharing, many 
researchers have pointed out the drawbacks of both criteria (Beeres and Bogers, 
2012; Oma, 2012; Bogers and Beeres, 2013, in Haesebrouck and Thiem 2018, p 751), 
causing some to further expand the set of criteria which constitute output measures.
Haesebrouck and Thiem (2018, p 751) also included the following criteria among 
the indicators of burden-sharing between the states: 
 – Risk exposure: different types of units are exposed to unequal levels of risk; 
particular distinction is made between the staff, medical, logistic and combat units 
forming individual contingents;
 – Leadership responsibility: whether a state has assumed a leadership role at the 
strategic or tactical level by providing the operation commander or deputy, and/or 
the force commander or deputy. Filling such positions represents a large burden 
for the providing state, particularly if complications occur during the operation; 
 – Mission duration: the longer the military units need to be sustained, the greater the 
burden which the state must bear.
Ringsmose (2010, p 328) suggested that research into military contributions by 
individual states in the form of deploying their troops to NATO missions and operations 
should consider two significant limitations. First, burden-sharing is not just about, or 
mainly about, debates on the number of troops contributed to an operation by a state, 
but also about sharing the risks arising from deploying troops to the most dangerous 
or security-wise unstable areas. Therefore, some countries choose to invoke certain 
national caveats in order to attempt to decrease the potential casualties, particularly 
if the public and the political leadership are not very supportive of deployments to 
dangerous areas. Alternatively, states attempt to avoid the deployment of too large 
a number of troops to dangerous areas by providing mission-relevant armaments as 
capabilities which are critical to the conduct of the operation (such as aircraft), thus 
making risk-free kinetic contributions to multinational operations14.
Based on past research into national military contributions to NATO missions and 
operations, it can be established that the factors used by various authors as measures 
or criteria of burden-sharing have included:
 – The number of participating/deployed troops relative to population size15;
 – The number of participating/deployed troops relative to the percentage of troops 
from all states participating in a NATO mission or operation;
14 For example, Belgium (F-16 jets) or Germany (Tornado jets). 
15 Cooper, for example, stated that due to the obvious impact of a state’s population size on its capacity to deploy 
troops, the number of deployed troops should be divided by 100,000 people (Cooper, 2011, p 5).
 – The number of fatal casualties relative to population size (Ringsmose, 2010);
 – Risk acceptance and distribution (depending on whether states deployed their 
troops to stable or unstable areas) (Ashraf, 2011);
 – Participation in offensive counter-terrorist and counter-insurgency military 
operations (Ashraf, 2011);
 – Participation in defensive civilian and military operations aimed at stabilizing a 
conflict-ridden state (Ashraf, 2011);
 – The invoking of national caveats (Ringsmose, 2010).
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Avg
Slovenia 8.9 7.5 10.8 7.4 21.4 22.5 19.7 19.3 19.3 17.4 15.9 15.2 12.6 12.5 12.0 14.8
Denmark 10.3 8.7 13.5 15.4 19.1 17.2 16.3 14.1 12.4 8.0 3.8 2.8 2.1 2.3 2.3 9.9
USA 1.0 0.7 4.7 5.6 6.9 9.6 23.2 29.1 26.2 20.5 9.6 2.3 2.3 2.3 2.8 9.8
UK 5.1 6.1 10.4 10.9 13.8 13.8 15.2 15.0 14.9 12.9 6.6 0.7 0.4 0.8 1.0 8.5
Estonia 3.8 2.5 11.0 10.7 11.7 12.7 11.4 12.2 11.6 12.4 5.1 0.5 0.5 0.5 2.4 7.3
Norway 7.2 9.5 9.4 12.1 10.7 10.6 9.3 8.5 8.0 2.6 1.6 1.0 0.7 0.8 1.1 6.2
Luxembourg 12.7 6.9 7.6 6.9 6.5 6.4 6.3 6.2 5.8 5.9 5.0 4.6 4.1 4.0 0.3 6.0
Italy 8.2 7.4 6.5 8.1 8.0 7.6 7.9 7.6 8.1 5.7 3.9 2.0 2.4 2.6 2.4 5.9
Greece 19.0 12.9 14.4 8.1 7.9 6.5 6.9 3.2 2.1 1.1 1.2 1.1 1.1 1.1 1.1 5.9
Germany 8.3 7.2 7.2 6.5 6.9 7.5 7.1 7.9 7.5 6.1 3.7 2.0 2.0 2.0 2.1 5.6
Hungary 5.7 6.7 4.4 6.9 5.5 5.7 6.3 6.9 6.2 5.3 4.5 4.6 4.6 4.7 4.9 5.5
Albania      5.3 9.0 9.3 9.3 5.9 2.2 1.9 1.9 3.4 4.9 5.3
Croatia      7.9 7.2 7.6 7.2 5.1 3.9 3.1 2.9 3.1 3.4 5.1
Netherlands 7.1 7.4 11.7 10.8 10.7 11.1 7.3 1.2 2.4 2.5 0.8 0.5 0.6 0.6 0.8 5.0
Romania 1.7 3.3 3.9 3.7 3.9 5.2 7.1 9.4 9.4 6.8 3.7 3.5 3.3 3.3 3.9 4.8
Lithuania 3.9 4.5 5.0 5.9 8.0 7.8 6.8 7.1 8.0 6.5 2.8 1.5 0.7 0.8 1.8 4.7
Czechia 4.6 5.1 7.1 7.7 7.4 8.0 5.5 6.1 4.8 2.2 2.3 2.3 2.1 2.1 2.7 4.7
Bulgaria 0.8 0.5 2.6 6.2 6.6 7.7 7.2 8.4 8.3 5.8 5.1 1.7 1.4 1.5 2.6 4.4
Canada 7.4 7.1 7.1 7.2 7.7 8.4 8.4 5.9 2.2 2.6 0.1 0.0 0.0 0.0 0.0 4.3
Belgium 7.2 6.9 6.5 7.0 5.4 6.3 5.1 4.7 4.1 1.8 1.1 0.5 0.5 0.5 0.7 3.9
Latvia 1.1 1.7 2.0 3.6 4.6 7.0 7.8 7.3 6.7 4.1 3.1 1.2 1.1 1.1 1.9 3.6
Slovakia 2.7 2.4 3.6 3.7 5.5 6.1 7.5 5.7 5.9 4.0 3.9 0.7 0.7 0.7 0.6 3.6
France 5.5 5.1 4.2 4.5 6.3 6.5 6.9 6.5 4.6 1.0 0.2 0.0 0.0 0.0 0.0 3.4
Poland 2.3 0.8 1.1 2.9 3.7 5.2 6.7 7.5 6.4 4.6 2.3 1.0 1.2 1.1 1.4 3.2
Portugal 6.2 4.6 4.6 4.4 3.5 3.4 4.1 2.7 2.9 3.1 2.4 1.9 1.9 0.2 1.4 3.1
Spain 4.3 3.0 3.1 2.8 3.0 1.7 2.9 3.2 3.2 1.8 0.5 0.5 0.0 0.0 0.1 2.0
Turkey 3.4 2.6 1.6 2.9 1.9 1.7 3.1 3.0 2.3 1.9 1.0 1.1 1.2 1.1 1.0 2.0
Iceland 0.0 6.7 0.0 2.6 2.8 2.5 1.3 1.3 1.2 0.9 0.9 0.9 0.6 0.6 0.6 1.5
NATO Avg 5.9 5.2 6.5 6.9 7.9 8.1 8.6 8.4 7.8 5.8 3.6 2.2 1.9 2.0 2.2 5.5
Špela Boc
 29 Sodobni vojaški izzivi/Contemporary Military Challenges
 – The number of fatal casualties relative to population size (Ringsmose, 2010);
 – Risk acceptance and distribution (depending on whether states deployed their 
troops to stable or unstable areas) (Ashraf, 2011);
 – Participation in offensive counter-terrorist and counter-insurgency military 
operations (Ashraf, 2011);
 – Participation in defensive civilian and military operations aimed at stabilizing a 
conflict-ridden state (Ashraf, 2011);
 – The invoking of national caveats (Ringsmose, 2010).
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Avg
Slovenia 8.9 7.5 10.8 7.4 21.4 22.5 19.7 19.3 19.3 17.4 15.9 15.2 12.6 12.5 12.0 14.8
Denmark 10.3 8.7 13.5 15.4 19.1 17.2 16.3 14.1 12.4 8.0 3.8 2.8 2.1 2.3 2.3 9.9
USA 1.0 0.7 4.7 5.6 6.9 9.6 23.2 29.1 26.2 20.5 9.6 2.3 2.3 2.3 2.8 9.8
UK 5.1 6.1 10.4 10.9 13.8 13.8 15.2 15.0 14.9 12.9 6.6 0.7 0.4 0.8 1.0 8.5
Estonia 3.8 2.5 11.0 10.7 11.7 12.7 11.4 12.2 11.6 12.4 5.1 0.5 0.5 0.5 2.4 7.3
Norway 7.2 9.5 9.4 12.1 10.7 10.6 9.3 8.5 8.0 2.6 1.6 1.0 0.7 0.8 1.1 6.2
Luxembourg 12.7 6.9 7.6 6.9 6.5 6.4 6.3 6.2 5.8 5.9 5.0 4.6 4.1 4.0 0.3 6.0
Italy 8.2 7.4 6.5 8.1 8.0 7.6 7.9 7.6 8.1 5.7 3.9 2.0 2.4 2.6 2.4 5.9
Greece 19.0 12.9 14.4 8.1 7.9 6.5 6.9 3.2 2.1 1.1 1.2 1.1 1.1 1.1 1.1 5.9
Germany 8.3 7.2 7.2 6.5 6.9 7.5 7.1 7.9 7.5 6.1 3.7 2.0 2.0 2.0 2.1 5.6
Hungary 5.7 6.7 4.4 6.9 5.5 5.7 6.3 6.9 6.2 5.3 4.5 4.6 4.6 4.7 4.9 5.5
Albania      5.3 9.0 9.3 9.3 5.9 2.2 1.9 1.9 3.4 4.9 5.3
Croatia      7.9 7.2 7.6 7.2 5.1 3.9 3.1 2.9 3.1 3.4 5.1
Netherlands 7.1 7.4 11.7 10.8 10.7 11.1 7.3 1.2 2.4 2.5 0.8 0.5 0.6 0.6 0.8 5.0
Romania 1.7 3.3 3.9 3.7 3.9 5.2 7.1 9.4 9.4 6.8 3.7 3.5 3.3 3.3 3.9 4.8
Lithuania 3.9 4.5 5.0 5.9 8.0 7.8 6.8 7.1 8.0 6.5 2.8 1.5 0.7 0.8 1.8 4.7
Czechia 4.6 5.1 7.1 7.7 7.4 8.0 5.5 6.1 4.8 2.2 2.3 2.3 2.1 2.1 2.7 4.7
Bulgaria 0.8 0.5 2.6 6.2 6.6 7.7 7.2 8.4 8.3 5.8 5.1 1.7 1.4 1.5 2.6 4.4
Canada 7.4 7.1 7.1 7.2 7.7 8.4 8.4 5.9 2.2 2.6 0.1 0.0 0.0 0.0 0.0 4.3
Belgium 7.2 6.9 6.5 7.0 5.4 6.3 5.1 4.7 4.1 1.8 1.1 0.5 0.5 0.5 0.7 3.9
Latvia 1.1 1.7 2.0 3.6 4.6 7.0 7.8 7.3 6.7 4.1 3.1 1.2 1.1 1.1 1.9 3.6
Slovakia 2.7 2.4 3.6 3.7 5.5 6.1 7.5 5.7 5.9 4.0 3.9 0.7 0.7 0.7 0.6 3.6
France 5.5 5.1 4.2 4.5 6.3 6.5 6.9 6.5 4.6 1.0 0.2 0.0 0.0 0.0 0.0 3.4
Poland 2.3 0.8 1.1 2.9 3.7 5.2 6.7 7.5 6.4 4.6 2.3 1.0 1.2 1.1 1.4 3.2
Portugal 6.2 4.6 4.6 4.4 3.5 3.4 4.1 2.7 2.9 3.1 2.4 1.9 1.9 0.2 1.4 3.1
Spain 4.3 3.0 3.1 2.8 3.0 1.7 2.9 3.2 3.2 1.8 0.5 0.5 0.0 0.0 0.1 2.0
Turkey 3.4 2.6 1.6 2.9 1.9 1.7 3.1 3.0 2.3 1.9 1.0 1.1 1.2 1.1 1.0 2.0
Iceland 0.0 6.7 0.0 2.6 2.8 2.5 1.3 1.3 1.2 0.9 0.9 0.9 0.6 0.6 0.6 1.5
NATO Avg 5.9 5.2 6.5 6.9 7.9 8.1 8.6 8.4 7.8 5.8 3.6 2.2 1.9 2.0 2.2 5.5
Table 2: 
Rate of 
deployment 
to operations 
outside the 
territories of 
NATO Member 
States per 
100,000 of 
the population 
(Source: Who 
commits the 
most to NATO? 
It depends 
on how we 
measure 
commitment 
(Cooper and 
Stiles, 2021, p 6)
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
 30 Sodobni vojaški izzivi/Contemporary Military Challenges
A recent piece of research into how much individual Member States contributed 
to NATO and how their contributions reflected their commitment to NATO was 
conducted by Cooper and Stiles (2021). Examining the number of troops (the 
deployment rate) deployed by individual NATO members to NATO missions in 
Kosovo, Bosnia and Herzegovina, Iraq and Afghanistan from 2004 to 2018, they 
found large disparities in burden-sharing between Alliance members16. They found 
that states such as Slovenia, Denmark, the US and the United Kingdom contributed 
far more troops to NATO missions than Turkey, Spain, Poland or Portugal (Cooper 
and Stiles, 2021, p 1).
Both France and Turkey have a high proportion of defence expenditure, but contribute 
a less-than-average number of troops to NATO missions. In contrast, Slovenia and 
Denmark provide a much higher degree of support to NATO operations than one 
might expect based on their defence expenditure. In terms of the number of troops 
deployed to NATO missions and operations per 100,000 of the population, in the 
period between 2004 and 2018 Slovenia had the highest deployment rate, with nearly 
15 deployed members per 100,000 people. With an average of two deployed troops 
per 100,000 people, Turkey ranked at the bottom (Cooper and Stiles, 2021, pp 2-5).
 4 ALLIED INTERVENTION IN AFGHANISTAN – A TEST OF BURDEN-
SHARING 
The mission in Afghanistan was the most ambitious and extensive in terms of the 
contributions of multinational forces (land, air and naval units and assets) and the 
types of operational task (Hanagan, 2017). The ISAF operation represented a new era 
in terms of views and positions on burden-sharing and in terms of implementing new, 
more complex perceptions of burden-sharing between the states (Jakobsen, 2018). It 
represented the beginning of an increase in the number of NATO military operations, 
while the nature of the operations gradually began to shift from peacekeeping to 
warfare, requiring extensive military contributions (Paljak, in Molder, 2014, p 64). 
Larger Alliance members saw the ISAF as a litmus test of the capabilities of the 
Member States and their preparedness to counter threats to their security (Kaluga, 
2011, p 59). Furthermore, the operation was a test to verify the concept of partnerships 
established by NATO.
While the ISAF was a NATO-led operation, it was not a NATO-only operation, as 
it involved both NATO allies and a large number of non-NATO countries, each of 
which operated according to its own rules of engagement (Bjerg Moller, 2021). The 
ISAF operation became a network connecting NATO with partner states around the 
world both militarily and politically (Appathurai, in Flockhart, 2014, p 35).
16 As their deployment indicator, the authors used the number of troops deployed to operations outside the 
territories of NATO Member States per 100,000 of the population.
Špela Boc
 31 Sodobni vojaški izzivi/Contemporary Military Challenges
Similarly to other crisis areas, larger, more ambitious and wealthier states with 
greater military power took on a relatively larger share of the burden in Afghanistan. 
This was also reflected in the extent and scope of assistance, in the size of individual 
national contingents, and in the scope and difficulty of military tasks. The US 
was the only country capable of carrying out the entire scope of tasks completely 
independently (Milovac, 2016, p 256). 
In defining the roles of the participating states in the ISAF operation, McNamara 
(2015, p 4) summarized Hynek and Marton, who determined four main roles 
assumed and performed by NATO allies in the context of joint burden-sharing within 
the ISAF operation:
 – The owner of the mission: the US, as controlling Afghanistan was a direct objective 
of its security policy;
 – The strivers: states reliant on NATO’s security provision, which as a consequence 
motivated them to make contributions (goods) judged as premium or very 
important by the mission owner;
 – Servants: states contributing goods deemed less important by the lead nation;
 – Onlookers: states with a weak motivation which made only superficial 
contributions.
Above all, the ISAF operation and the subsequent RSM mission represented great 
challenges for smaller states – both for Alliance members and partner states striving 
or already preparing for NATO membership. While contributing to activities in 
Afghanistan, some of these states were also part of other NATO, UN and EU-led 
military operations. This posed a great challenge to the military planners of small 
states, as these states needed to find additional capabilities for the most extensive 
NATO operation of the time.
Therefore, as Urbelis writes (2015, p 67): »The NATO mission in Afghanistan 
provided a good opportunity for small states to prove their resolve, solidarity and 
demonstrate military capabilities«. The type of qualitative and quantitative military 
contributions, in particular, was an indicator of the political will of the small states, 
as it reflected their commitment and responsibility in the context of burden-sharing 
within NATO, and of their efforts to become NATO members.
Some authors also applied quantitative or mathematical methods in their research 
into burden-sharing in the ISAF operation. Becker, for example, examined whether 
the evolution of burden-sharing within NATO was also reflected in the participation 
of NATO Member States in the ISAF operation. To that end, he devised the 
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
 32 Sodobni vojaški izzivi/Contemporary Military Challenges
Burden-Sharing Index (BSI)17, aimed at illustrating the operational cooperation of 
NATO allies in the ISAF operation (Becker, 2011).
BSI =
NATO Cost Share
NATO Benefit Share
=
Member MILEX | Total NATO MILEX
(Member GDP + Member Popo. + Member Urban Pop.) | NATO Total
Becker established that NATO members had operationalized their military expenditure 
in Afghanistan in very diverse ways, and that the operation had been a serious test 
of the cohesion of the Alliance. In his assessment, the most concerning issue was the 
fairly disproportionate burden-sharing between NATO Member States within the 
ISAF operation, with particularly significant disparities between the contributions of 
the US and European allies (Becker, 2011, pp 64-65).
The assessment and determination of appropriate and, above all, fair burden-sharing 
within the Alliance is not an easy process, as it takes many forms and is particularly 
dependent on periods and turning points of strategic importance for NATO. It 
has been confirmed that the evaluation of the scope and size of burden-sharing 
is complicated even if the individual elements are measurable. The evaluation of 
quantitative criteria, in particular, can therefore lead to different results due to specific 
difficulties in measuring, quantifying and interpreting the data. The analysis of the 
issues of burden-sharing and contributions made by states has confirmed that the 
interpretation of the term burden-sharing, and the approaches to addressing it, have 
varied throughout the different periods of the Alliance’s development and during the 
various security challenges it has faced.
One of the crucial findings is that burden-sharing concerns capacities to contribute to 
the security of the Alliance which are reflected and measured in various ways or forms 
and based on various parameters. Despite all the attempts to reduce the disparities, 
the different national positions on appropriate burden-sharing, and the search for 
17 »To get to the ISAF BSI and the PR, »military burden« is used to measure military expenditures and their 
economic significance and impact, and is defined as the ratio of military expenditures to the Gross Domestic 
Product. The »burden sharing index« (BSI) is an indicator developed specifically for this paper, based on the 
work of Sandler and Hartley (1999). The index is designed as a proxy for the cost/benefit ratio associated with 
each member’s participation in NATO. BSI is calculated by dividing the NATO Cost Share of each member 
(member military expenditures divided by total NATO military expenditures) for each year by the NATO 
Benefit Share of each member (member benefits divided by total NATO benefits). Benefit share expresses 
benefits as a function of economic goods protected (GDP) and human lives protected (population, with urban 
population weighted additionally to account for both the increased vulnerability of urban dwellers and their 
disproportionate contribution to GDP) (Becker, 2011, p 50).«
Conclusion
Figure 1: 
The Burden-
Sharing Index 
(BSI)
(Source: Becker, 
2011, p 50)
Špela Boc
 33 Sodobni vojaški izzivi/Contemporary Military Challenges
Burden-Sharing Index (BSI)17, aimed at illustrating the operational cooperation of 
NATO allies in the ISAF operation (Becker, 2011).
BSI =
NATO Cost Share
NATO Benefit Share
=
Member MILEX | Total NATO MILEX
(Member GDP + Member Popo. + Member Urban Pop.) | NATO Total
Becker established that NATO members had operationalized their military expenditure 
in Afghanistan in very diverse ways, and that the operation had been a serious test 
of the cohesion of the Alliance. In his assessment, the most concerning issue was the 
fairly disproportionate burden-sharing between NATO Member States within the 
ISAF operation, with particularly significant disparities between the contributions of 
the US and European allies (Becker, 2011, pp 64-65).
The assessment and determination of appropriate and, above all, fair burden-sharing 
within the Alliance is not an easy process, as it takes many forms and is particularly 
dependent on periods and turning points of strategic importance for NATO. It 
has been confirmed that the evaluation of the scope and size of burden-sharing 
is complicated even if the individual elements are measurable. The evaluation of 
quantitative criteria, in particular, can therefore lead to different results due to specific 
difficulties in measuring, quantifying and interpreting the data. The analysis of the 
issues of burden-sharing and contributions made by states has confirmed that the 
interpretation of the term burden-sharing, and the approaches to addressing it, have 
varied throughout the different periods of the Alliance’s development and during the 
various security challenges it has faced.
One of the crucial findings is that burden-sharing concerns capacities to contribute to 
the security of the Alliance which are reflected and measured in various ways or forms 
and based on various parameters. Despite all the attempts to reduce the disparities, 
the different national positions on appropriate burden-sharing, and the search for 
17 »To get to the ISAF BSI and the PR, »military burden« is used to measure military expenditures and their 
economic significance and impact, and is defined as the ratio of military expenditures to the Gross Domestic 
Product. The »burden sharing index« (BSI) is an indicator developed specifically for this paper, based on the 
work of Sandler and Hartley (1999). The index is designed as a proxy for the cost/benefit ratio associated with 
each member’s participation in NATO. BSI is calculated by dividing the NATO Cost Share of each member 
(member military expenditures divided by total NATO military expenditures) for each year by the NATO 
Benefit Share of each member (member benefits divided by total NATO benefits). Benefit share expresses 
benefits as a function of economic goods protected (GDP) and human lives protected (population, with urban 
population weighted additionally to account for both the increased vulnerability of urban dwellers and their 
disproportionate contribution to GDP) (Becker, 2011, p 50).«
appropriate criteria for contributions, it is easier to understand input measures than to 
determine and evaluate output measures. This is mostly because the output measures 
are not visible enough, as some states refuse to disclose them publicly.
The case of the ISAF operation, in particular, confirmed that some NATO Member 
States can remain credible allies, which do not act as free-riders, despite not fulfilling 
the »investment measures and criteria«. It has been demonstrated that states with 
limited financial resources can largely make up for not achieving the input measures 
by making other visible contributions to NATO’s military activities, operations and 
missions (including peacetime ones). Arguably, using an indicator which is focused 
solely on defence expenditure does not provide an insight into the increasingly 
diverse or multidimensional defence contributions made by the allies (such as 
deterrence, response, defence, crisis management operations or national operations) 
(Bogers, 2019: p 20).
In spite of this, and in the light of all the criticism levelled at the too-narrow focus 
(solely) on the 2% defence expenditure criterion of burden-sharing, this measure 
must be understood, first and foremost, as an expression of political will or national 
commitment. The proportion of defence expenditure would be a credible measure 
of fair burden-sharing if those states which spend a high percentage of their GDP 
on defence also contributed equally large or extensive military capabilities towards 
achieving common goods (security). 
In the current, increasingly complicated and unpredictable security environment, 
one could give credence to Cooper and Stiles’ assessment that future research 
should continue to focus on commitment indicators which encompass the broader 
contributions to the Alliance (2021, p 10). A single indicator for measuring 
burden-sharing is hardly applicable to all Member States, since states make their 
contributions in various ways. In addition, states will increasingly have to adapt their 
contributions as NATO’s Level of Ambition (LOA) changes. The most objective 
representation or calculation of burden-sharing would be based on accounting for 
both quantitative and qualitative criteria for measuring contributions, since the total 
impact of measurable and non-measurable contributions reflects how productive 
and successful an individual state is as an Alliance member, and what its actual 
share in the collective burden-sharing is. Even more importantly, analyses of defence 
expenditure data, and the expenditure on NATO operations and missions, should 
focus on how such expenditure is used, rather than how much of it is spent.
It has turned out that NATO is undergoing adjustment processes in which the 
proportion of GDP allocated for defence will no longer be the main burden-sharing 
criterion for which states should strive. States will increasingly have to  contribute to 
NATO’s persistent federated approach, aimed at achieving interoperability standards 
to ensure constant readiness (Delaporte, 2018). 
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
 34 Sodobni vojaški izzivi/Contemporary Military Challenges
In the current period of the Alliance, when the allies are mostly engaged in activities 
of deterrence, defence and resilience to emerging or changed security threats and 
challenges, research into appropriate burden-sharing should also be directed towards 
attempts to search and define criteria for states to contribute to such (changed) 
Alliance activities.
1. Ashraf, A., 2011. The Politics of Coalition Burden-Sharing: The Case of the War in 
Afghanistan. Pittsburgh: University of Pittsburgh.
2. Bell, R. G., 2022. Fixing NATO’s 2014 Defense Investment Pledge. and CSDP Policy 
Brief, 2022 (3). https://brussels-school.be/sites/default/files/CSDS%20Policy%20
brief_2203.pdf.
3. Becker, J., 2011. Transatlantic Burden Sharing and Out of Area Operations: Afghanistan 
in the Context of Historic Trends. Chicago Policy Review, 2011 (15), pp 47-67.
4. Becker, J., 2017. Transatlantic Burden-Sharing: Origins and Strategic Implications. 
https://defenceindepth.co/2017/11/15/transatlantic-burden-sharing-origins-and-strategic-
implications/, 12/8/2022.
5. Becker, J., and Malesky, E., 2017. The continent or the ‘grand large’? Strategic culture 
and operational burden-sharing in NATO. International Studies Quarterly 61(1): pp 163-
180. 
6. Binnendijk, H., 2018. What NATO’s burden-sharing history teaches us, https://www.
defensenews.com/smr/nato-priorities/2018/07/09/what-natos-burden-sharing-history-
teaches-us/, 22/7/2022.
7. Bjerg, Moller, S., 2021. Five Myths About NATO and Afghanistan. https://www.
lawfareblog.com/five-myths-about-nato-and-afghanistan#, 10/5/2022.
8. Forster, P. K., and Cimbala, S. J., 2005. The US NATO and Military Burden Sharing. 
London, New York: Frank Cass.
9. Cooper, S., and Stiles K. W., 2021. Who commits the most to NATO? 
It depends on how we measure commitment. Journal of Peace Research XX(X): pp 1-13. 
10. Cooper, C., A., and Zycher, B., 1989. Perceptions of NATO Burden-Sharing. Santa 
Monica: The Rand Corporation.  https://www.rand.org/pubs/reports/R3750.html, 
19/8/2022.
11. Delaporte, M., (2018). NATO’s Backstage: Working the »3 Cs« Rules at Allied Command 
Transformation. https://defense.info/featured-story/2018/04/natos-backstage-working-the-
3-cs-rules-at-allied-command-transformation/, 12/7/2022.
12. Flockhart, T., 2014. Introduction. Changing Partnerships in a Changing World, 
Cooperative Security: NATO’s Partnership Policy in a Changing World, DIIS Report, pp 
17-34. https://www.files.ethz.ch/isn/177617/WP2014-01_NATO-partnerships_TFL_web.
pdf, 25/10/2021. 
13. Hanagan, D. L., 2017. NATO And Coalition Warfare In Afghanistan, 2001-2014. London: 
King’s College.
14. Hartley, K., and Sandler, T., 1999. NATO Burden-Sharing: Past and Future, Journal of 
Peace Research. 36 (6), pp 665-80.
15. Haesebrouck, T., and Thiem, A., 2018. Burden Sharing in CSDP Military Operations. 
Defence and Peace Economics, 29 (7), pp 748-765.
References
Špela Boc
 35 Sodobni vojaški izzivi/Contemporary Military Challenges
16. Hicks, K. H., Rathke, J., Daniels, S. P., Matlaga, M., Daniels, L., and Linder, A., 2018. 
Counting Dollars or Measuring Value. Assessing NATO and Partner Burden Sharing. 
Washington, DC: CSIS.
17. Hillison, J., R., 2014. Stepping Up: Burden Sharing by NATO’s Newest Members. Carlisle 
Barracks, PA: United States Army War College Press.
18. Hudhra, T., 2018. Defence Planning System of Albania in the Framework of NATO 
Collective Planning System. Tirana: Academy of the Armed Forces.
19. Jakobsen, J., 2018. Is European NATO Really free-riding? Patterns of Material and Non-
Material Burden-Sharing After the Cold War. European Security 27(4): 1-25. https://doi.
org./10.1080/09662839.2018.1515072, 22/7/2022.
20. Jazbec, G., 2009. Foreign Policy Formation in the Context of Understanding 
Peacekeeping Operations. The Slovenian Armed Forces Bulletin, 11(1), SAF GS, 
Ljubljana, 2009, pp 99-116.
21. Kaluga, B., 2011. The International Context of the Central European States Participation 
in the Afghan Stabilization mission. Morgantown: Eberly College of Arts and Sciences at 
West Virginia University.
22. Kavanagh, J. et al., 2021. Building Military Coalitions. Lessons from U.S. Experience, 
https://www.rand.org/pubs/research_reports/RRA859-1.html, 12/7/2022.
23. Kivimäki, T., 2019. Power, Contribution and Dependence in NATO Burden Sharing. 
European Security, 20:1, pp 66-84.
24. Kingsley, R., 2014. Fighting against Allies: An Examination of »National Caveats« Within 
the NATO-led International Security Assistance Force (ISAF) Campaign in Afghanistan 
and their Impact on ISAF Operational Effectiveness 2002-2012. Manawatu: Massey 
University.
25. Koivula, T., 2021. Carry That Weight: Assessing Continuity and Change in NATO’s 
Burden-Sharing Disputes. Defense & Security Analysis, 37:2, pp 145-163.
26. Kreps, S., 2007. When Does the Mission Determine the Coalition? The Logic of 
Multilateral Interventions under Unipolarity. Washington, DC: Graduate School of Arts 
and Science of Georgetown University.
27. Mannik, E., 2004. Small States: Invited to NATO – Able to Contribute? Defence & 
Security Analysis, 20;1, pp 21-37. 
28. McNamara, M. E., 2015. When Contributions Abroad Mean Security at Home? The Baltic 
States and NATO Burden-Sharing in Afghanistan. https://www.academia.edu/9027180/
When_Contributions_Abroad_Mean_Security_at_Home_The_Baltic_States_and_NATO_
Burden_Sharing_in_Afghanistan, 12/10/2020.
29. Milovac, B., 2016. Značilnosti teoretičnega obravnavanja načina vojskovanja razvitih 
držav po koncu hladne vojne (»Characteristics of a Theoretical Study of a Way of Warfare 
of Developed Countries in the Post-Cold War Era«). Ljubljana: Faculty of Social 
Sciences.
30. Mattelaer, A., 2016. Revisiting the Principles of NATO Burden-Sharing. Parameters 46. 
https://press.armywarcollege.edu/cgi/viewcontent.cgi?article=2821&context=paramete
rs, 12/7/2022.
31. Molder, H., 2013. Estonia and the ISAF: Lessons Learned and Future Prospects. The 
Polish Quarterly of International Affairs, 23(2): pp 61-78.
32.  NATO, 2019. The North Atlantic Treaty. https://www.nato.int/cps/en/natolive/official_
texts_17120.htm, 19/7/2022.
33. NATO, 2022a. Defence Expenditure of NATO States (2014-2022).  https://www.nato.int/
nato_static_fl2014/assets/pdf/2022/6/pdf/220627-def-exp-2022-en.pdf, 20/7/2022.
34. NATO, 2022b. Funding NATO. https://www.nato.int/cps/en/natohq/topics_67655.htm, 
20/7/2022.
MILITARY BURDEN-SHARING WITHIN THE ALLIANCE 
 36 Sodobni vojaški izzivi/Contemporary Military Challenges
35. NATO document, 2017. Summary Note to Council on the Need to Improve NATO’s 
Capability Package Process. https://www.nato.int/issues/iban/performance_
audits/170201-improve-capability-package-process-eng.pdf, 17/8/2022.
36. Oma, I., 2012. Explaining States’ Burden-Sharing Behaviour Within NATO. Cooperation 
and Conflict 47(4): pp 562-573.
37. Pavlíčková, K., and Bartoszewicz M. G., 2020. To Free or not to Free (Ride): A 
Comparative Analysis of the NATO Burden-Sharing in the Czech Republic and Lithuania. 
Defense & Security Analysis, https://www.researchgate.net/publication/337199208_To_
Free_or_Not_to_Free_Ride_A_Comparative_Analysis_of_the_NATO_Burden Sharing_
in_the_Czech_Republic_and_Lithuania, 20/7/2022.
38. Polajžer, T., 2013. Jugosfera: fikcija ali resničnost? (»Yugosphere: Fiction or Reality?«). 
Ljubljana: Faculty of Social Sciences.
39. US Budget, 2023. North Atlantic Treaty Organization 
Security Investment Program. April 2022. https://comptroller.defense.gov/portals/45/
documents/defbudget/fy2023/budget_justification/pdfs/11_nato_security_investment_
program/fy23_nato_security_investment_program.pdf, 17/7/2022.
40. Ringsmose, J., 2010. NATO Burden-Sharing Redux: Continuity and Change after the Cold 
War. Contemporary Security Policy, 31(2), pp 319-338.
41. Rotfeld, A., D., 1994. Europe: Towards a New Regional Security Regime. SIPRI Yearbook 
1994. https://www.sipri.org/yearbook/1994/07, 24/7/2022.
42. Ržen, J., 2013. Vpliv vključenosti Republike Slovenije v sistem obrambnega planiranja 
Nata na razvoj zmogljivosti njenega obrambnega Sistema (»The Impact of the Republic 
of Slovenia’s Inclusion in the NATO Defence Planning System on the Capabilities 
Development of its Defence System«). Ljubljana: Faculty of Social Sciences.
43. Sperling, J., and Webber, M., 2009. NATO. From Kosovo to Kabul, May 
2009, International Affairs 85(3): pp 491-511, https://www.researchgate.net/
publication/227652515_Nato_From_Kosovo_to_Kabul, 18/7/2022.
44. Šavc, P., 2009. The Slovenian Experience of Defence Planning and NATO Membership. 
The Slovenian Armed Forces Bulletin (11/No. 3), pp 41-58 Ljubljana: General Staff of the 
Slovenian Armed Forces. 
45. Urbelis, V., 2015. The Relevance and Influence of Small States in NATO and the EU 
Common Foreign and Security Policy. Lithuanian Annual Strategic Review, 2014-2015, 
Volume 13, pp 61-78.
46. Zyla, B., 2016. NATO Burden Sharing: A New Research Agenda. JIOS, 7 (2), pp 5-21 
http://journal-iostudies.org/sites/default/files/2020-01/JIOS_Fall2016_Zyla-NATO_0.pdf, 
20/7/2022.
47. Zycher, B., 1990. A Generalized Approach for Analysis of Alliance Burden Sharing. Santa 
Monica: The Rand Corporation. https://www.rand.org/pubs/notes/N3047.html, 15/7/2022.
48. Žerjavič, P., 2017. Trump, Nato in trojni C (»Trump, NATO and the Triple C«). Delo, 
25/5. https://old.delo.si/svet/evropa/trump-nato-in-trojni-c.html, 15/7/2022.
email: spela.boc@mors.si
Špela Boc
e-mail: spela.boc@mors.si
Špela Boc je magistrica politologije s specializacijo iz obramboslovja. Podiplomski 
študij je zaključila na Fakulteti za državne in evropske študije, kjer je doktorska 
kandidatka. Na Ministrstvu za obrambo je zaposlena od leta 2004, sodelovala je 
v treh mirovnih operacijah in na misijah ter dodatno strokovno znanje pridobivala 
na različnih domačih in mednarodnih izobraževanjih, konferencah in seminarjih. Je 
avtorica ali soavtorica več člankov. Obiskovala je tečaje na Harvard Kennedy School 
of Government v Bostonu.
Špela Boc holds an MA in Political Studies with a specialization in Defence Studies. 
She completed her postgraduate studies at the Faculty of Government and European 
Studies, where she is a PhD candidate. Employed by the Ministry of Defence since 
2004, she has participated in three peacekeeping operations and missions and gained 
additional expertise in various national and international training programmes, 
conferences and seminars. She has authored or co-authored several papers and 
attended courses at the Harvard Kennedy School of Government in Boston. 
*Prispevki, objavljeni v Sodobnih vojaških izzivih, niso uradno stališče Slovenske 
vojske niti organov, iz katerih so avtorji prispevkov.
*Articles, published in the Contemporary Military Challenges do not reflect the 
official viewpoint of the Slovenian Armed Forces nor the bodies in which the authors 
of articles are employed.