The Survival and Breakdown of Victorious War
Coalitions∗
Scott Wolford
[email protected]
August 5, 2014
Abstract
States often take on coalition partners to secure victory in war, but afterwards
their members may fall into conflict over the terms of the peace just secured, often at tremendous cost. What distinguishes those victorious coalitions that manage to sustain cooperation from those that disintegrate into hostility? To answer
this question, I gather data on the characteristics of victorious wartime coalitions
from 1859 to the present and estimate the duration of cooperation between their
members in an event history framework. I explore the effects of coalition size, the
diversity of preferences within the coalition, wartime alliance commitments, military strength, and several features of the war itself on the sustainability of peace
amongst the members of victorious coalitions. While large coalitions are uniquely
likely to break down, so are those with (a) diverse preferences and, surprisingly, (b)
those comprised of a larger proportion of allies.
∗
Draft version; comments welcome, but please do not cite without permission. Prepared for presentation at the 2014 Annual Meeting of the American Political Science Association, 28 August, Washington,
DC. Draft version; comments welcome, but please do not cite without permission. Thanks to Dan McCormack and Toby Rider for helpful comments and suggestions.
Mere months after the end of the First Balkan War in 1913, the members of the Balkan
League fell into open conflict over the spoils of their victory. Unable to agree over the division of newly captured territories in Ottoman Europe, Bulgaria fought its former partners, Serbia and Greece, in the Second Balkan War (Hall 2000), heightening the regional
rivalries that would ultimately play a role in the opening of the First World War (Clark
2012, Ch. 5,6). Many coalitions, on the other hand, win their wars and manage to cooperate much longer in maintaining the peace just secured; for example, Brazil, Argentina,
and Urugray have avoided war with one another since defeating Paraguay in the Lopez
War of 1870 (Abente 1987, Bethell 1996), and the broad coalition that won the Gulf War
of 1991 (Atkinson 1993, Freedman and Karsh 1991) has also yet to see its members go
to war. What accounts for these differences? Why do some winning coalitions fall apart,
descending into open warfare soon after defeating a common enemy, while others share
the spoils of victory peacefully for years or decades afterwards?
Coalitions have participated in 40% of interstate wars in the past two centuries (Sarkees and Wayman 2010), fighting to preserve or restore of the status quo, to overturn
the balance of power, or to maintain the balance against rising challengers. Multilateral
wars tend to be longer (Slantchev 2004), deadlier (Shirkey 2012), and more consequential than bilateral wars, and after their common victory coalition members face a unique
challenge that single victors do not: cooperating in the maintenance of the peace just
secured (Wagner 2004, 2007). Fighting over the spoils of victory is doubly tragic, due to
both the inherent costs of fighting and the fact that victory had been, until recently, a
common goal. States undoubtedly have incentives to choose partners with whom they
are unlikely to fall into conflict after the war, but the exigencies of securing victory in the
first place often lead them to take on partners that, in less desperate times, they would
surely avoid (Starr 1972, Wolford 2014a). Unforseen problems might also arise after the
war that turn formerly reliable partners into enemies. However erstwhile victors turn
1
into adversaries, hard-won peace can be undermined, and, at the extreme, global orders constructed after major systemic wars can distintegrate in new conflagrations.
The stability of postwar peace is generally studied in the context of recurrent war between former belligerents (see, e.g., Fortna 2003, Lo, Hashimoto and Reiter 2008, Werner
1999, Werner and Yuen 2005), but, as attested by the example of the Balkan Wars above,
peace among the victors of a multilateral war can be especially precarious—and its breakdown no less consequential. Just as war can change the environment in which erstwhile
enemies interact (Morey 2011b), it can do the same for former partners (Wagner 2004,
2007). To explore this link between shared victory and the stability of postwar peace,
I analyze data on victorious coalitions in war over the last two centuries and the duration of peace between their members, which proxies for the stability of cooperation
over the postwar settlement. Using an event history framework, I estimate the effects
of coalition size (Riker 1962), preference diversity (Wolford 2014b), and formal alliance
commitments on the durability of post-victory peace, finding that all three—perhaps
surprisingly, in the case of alliance commitments—tend to shorten the time between
victory and subsequent war between former partners in victorious coalitions.
Thus, in addition to its immediate chances of winning wars (Morey 2011a) and provoking counter-coalitions (Wolford 2014b), as well as its share of the subsequent spoils
(Starr 1972), a state’s choice of coalition partner can also affect the subsequent durability
of whatever new peace follows the defeat of a common opponent. All else equal, small
coalitions with homogeneous preferences and a minimum of formal alliance commitments appear to be the most conducive to durable peace amongst the victors of war.
The rationales behind the effects of size and preference diversity are straightforward,
but the destabilizing effect of alliances is surprising. However, since allied pairs are also
the most likely amongst former partners to fall into conflict, the relationship is consistent with the notion that states tend to bind one another into formal commitments
2
when they expect that cooperation will be difficult. Therefore, treaties of alliance may be
symptomatic of an underlying obstacle to cooperation (Gibler and Rider 2004), a latent
problem that becomes manifest once an immediate common threat is eliminated by victory in war. Broadly, the empirical model shows that the stability of peace after wars is a
function of the postwar settlements reached not just between erstwhile belligerents, as
the literature shows, but also between former partners—a common and consequential
but heretofore unexplored problem in the study of international war and peace.
War and Coalitional Durability
Whether they pursue votes, the passage of legislation, or the submission of their enemies in war, coalitions of various stripes have one goal in common: winning (Riker
1962). However, building a coalition is expensive, as potential partners must be compensated for their cooperation with side payments or shares of the spoils of success, and
their price can be quite high when cooperation entails participating in a war. States generally try to minimize the compensation they must pay by choosing cheap partners, but
when desperate for military help, “war partners will be willing to forego greater shares
of the spoils to assure victory” (Starr 1972, p. 53). The Allies in the Second World War, for
example, needed Soviet support to defeat Nazi Germany, and despite its recent alignment with Germany and the certainty of fraught postwar peace negotiations, they allied with Stalin’s Soviet Union, “their military purposes mortgaged in advance” (Kennan
1984, p. 77), in hopes of securing victory in the short-term.
On balance, durable coalitions—i.e., those that won’t fall into open conflict after
victory—are quite attractive: why fight a war with a partner today that one will only go
on to fight in the future? However, durable coalitions can also represent such substantial threats to potential future enemies that fearful third parties join today’s war, siding
3
with a coalition’s target in order to eliminate a future threat before it grows too powerful (Wolford 2014b). Indeed, states often try to choose partners to avoid precisely that
problem; the United States, for example, worked hard to keep Taiwan out of its Korean
War coalition (Stueck 1995, 2004) and Israel out of its 1991 Gulf War coalition (Atkinson
1993) in order to reassure potentially fearful third-party states that a coalitional victory
would not represent subsequent threats to their interests.
We should thus expect that coalitions will vary in their ability to cooperate in maintaining the peace secured by victory in war. Among those factors proposed to accelerate
the dissolution of coalitions, three are particularly relevant in the context of interstate
war. First, Riker (1962) argues that size, often critical to secure an initial victory, becomes a liability once the victors must divide the spoils amongst themselves. His “size
principle” implies that states should take on only as many partners as required to secure
victory, and coalitions that turn out to be too large after victory will be winnowed down,
adjusted to ensure that the winning coalition divides the spoils among as few members
as possible. Thus, larger winning coalitions should be associated with more conflict
over the fruits of victory than smaller winning coalitions. Second, Wolford (2014b) argues that coalitions with diverse preferences are less likely to survive intact after war
than more homogeneous coalitions. Coalitions with diverse foreign policy preferences,
often built out of short-term military necessity, are more likely to come into conflict over
the disposition of the spoils of victory than those with similar preferences, because the
latter are better able to find an agreeable division of the spoils that saves the costs of war
and more likely to agree on any given issue in the future.1
Finally, Wagner (2004) links victory in war to shifts in the distribtuion of power between coalition members. To the extent that victors can credibly commit not to use
1
When powerful, diverse coalitions are also uniquely likely to provoke counter-coalitions aimed at facilitating their future dissolution (Wolford 2014b).
4
newfound power against one another, the coalition should survive its post-victory peace
intact. However, if renegotiation is both attractive and cheap, former partners may fall
easily into conflict over the newly established peace. Measuring the credibility of commitments, however, is difficult. Homogeneous preferences, for example, might mean
that states are less concerned about each other’s gains in power or influence; this is consistent with the above-proposed effects of preference diversity.
Those states that enter a war as allies, on the other hand, might see the formality of
their commitments cut both ways.2 Allies might have a great deal of interests in common, which makes alliances attractive to form in the first place. However, alliances are
also most attractive when they tether otherwise unreliable states to one’s own foreign
policy (Gibler and Rider 2004); why use an alliance to signal or ensure behaviors that
other states already expect? To the extent that alliances are formed in the shadow of
a common threat, however, defeating that threat might bring otherwise dormant conflicts into the open by eliminating the cause for the alliance. In other words, alliances
are costly instruments of commitment, most likely to be used when commitment is not
automatic—that is, when the costs paid to ensure commitment are justified due to a
partner’s potential unreliability (Morrow 1994, 2000). At the other end of the spectrum,
closely aligned partners that do not need an alliance to cement cooperation might be far
less prone to subsequent conflict after defeating their common enemy.
A similar rationale supports each of these arguments: states fight wars, sometimes in
cooperation with one another, to impose their preferences on the terms of peace agreements that will follow (Wagner 2007). The terms of these settlements, quite intuitively,
affect the duration of peace between former belligerents (cf Werner and Yuen 2005).
However, when states work together to defeat an opponent, the divergent preferences
2
Alliances are distinguished from informal relationships, e.g. alignments, by their formalization in
treaties; alliances are written down, but alignments are not (Morrow 2000).
5
subordinated to a “tacit neutrality” (Gamson 1961, p. 374) in order to secure victory may
come to the surface once that goal has been achieved, meaning that distributive issues
between former partners can also lead to subsequent war. Nonetheless, the literature’s
focus on recurrent war between former belligerents (Fortna 2003, Lo, Hashimoto and
Reiter 2008, Werner 1999, Werner and Yuen 2005) has come at the cost of understanding
the crucial dyanmics of bargaining and war between the very states that cooperated to
win the war. In the following section, I specify and estimate an empirical model designed
to provide the first systematic analysis of this problem. What kinds of coalitions manage
to cooperate in sharing the spoils of victory, and what kinds of coalitions descend into
intramural conflict after defeating their common enemy?
Research Design
In this section, I discuss the construction of the relevant sample of victorious war coalitions, the collection and coding of key theoretical and control variables, and the specification of the Cox proportional-hazards model used to estimate the effect of the independent variables on the time between victory in war and conflict erupting between
former coalition partners. The event-history framework is ideal for analyzing the durability of coalitions, because it models the probability that a coalition stays intact—or that
it “survives”—given that it has survived until the present time (see Box-Steffensmeier
and Jones 2004). When any of a coalition’s members fall into war with one another, the
coalition “fails,” or exits the sample. The technique has been widely used to study the
duration of war (Bennett and Stam 1996, Goemans 2000, Slantchev 2004) and the duration of postwar peace between former belligerents (Fortna 2003, Lo, Hashimoto and
Reiter 2008, Werner 1999, Werner and Yuen 2005), but I apply it here to the unique problem of postwar peace between former partners.
6
Assessing the durability of post-victory cooperation requires, first, identifying those
coalitions that win interstate wars. To do so, I use the Correlates of War project’s list
of interstate wars from 1816-2010 (Sarkees and Wayman 2010), which identifies twenty
victorious coalitions in interstate wars, starting with France, Austria, and the Kingdom
of the Two Sicilies’ victory in the War of the Roman Republic in 1849 and ending with
the topping of Iraq’s government during the interstate phase of the Iraq War in 2003 by
the United States, United Kingdom, and Australia.3 Table 2, which can be found in the
Appendix, lists the coalitions and their members that COW identifies as winning their
wars, generated by eliminating all bilateral wars, as well as those in which coalitions
lose to single belligerents. The remaining wars are those won by coalitions, as opposed
those in which coalitions lose or see the war end in stalemate.4 Some wars transition to
another type of war, often intra-state if conquest opens the door to insurgency; in these
cases, if the interstate phase had a clear winner—like the Iraq War, in which the coalition
successfully toppled the target government before the emergence of the insurgency—I
coded the war’s end at the transition point and recorded the outcome accordingly.5
Eleven coalitions, roughly half the sample, see a war break out amongst at least two
of their members after victory and before the end of the observation period in 2010, the
first of which for a coalition marks the end of cooperation and serves as the indicator of
“failure” by which coalitions exit the data.6 To be sure, coalitions may see cooperation
break down in a number of ways short of full-scale war, but using war as a measure of
coalitional dissolution has two advantages. First, all states can, in principle, go to war
3
COW’s operational definition of coalition membership differs from Wolford’s (2014b), which includes basing and staging contributions, meaning that Kuwait, from which the 2003 invasion of Iraq was
launched, would count as a member of the Iraq War coalition.
4
See Starr (1972) for an analysis of the distribution of payoffs between both winning and losing coalitions.
5
This leads to the inclusion of the War Over Angola (COW #186), Phase Two of the Second Ogaden War
(COW #187), the 2001 Invasion of Afghanistan (COW #225), and the 2003 Iraq War (COW #227).
6
There are also no “ties,” in that no wars erupt the same number of days after victory, making the choice
of how to handle ties irrelevant.
7
with one another, and they may do so over a variety of issues. Therefore, intramural
war as a measure of coalitional breakdown does not depend on the issues involved in
the war just ended or the specific terms imposed after victory; in contrast, indicators
short of war—say, abrograted alliances (Leeds and Savun 2007, Leeds, Mattes and Vogel
2009)—might. Second, as a relatively coarse indicator, war is also less prone to measurement error than some more inclusive alternative variables, such as lower-level disputes
or diplomatic tensions (e.g. Ghosn, Palmer and Bremer 2004, Wilkenfeld and Brecher
2010); when war erupts between two states, there is little doubt that security cooperation between them has broken down.
There are three key independent variables of interest: the number of states in the
coalition (Riker 1962), the diversity of preferences amongst its members (Wolford 2014b),
and extent to which the members of the coalition are tied to one another by formal alliances at the outbreak of war. Collecting data on the size principle is straightforward;
the variable Size is simply the number of states that COW identifies as members of the
victorious coalition (Sarkees and Wayman 2010). Measuring the diversity of preferences
inside coalitions is more difficult. Ideally, we would like a measure of revealed preferences, such as ideal points estimated from voting patterns in the UN General Assembly
(Reed et al. 2008, Strezhnev and Voeten 2013), but the limited temporal coverage—such
data is nonexistent before 1946—eliminates too much of the sample. Therefore, as a
rough proxy of the diversity of preferences inside the coalition, I create the variable Diversity by calculating the variance of the Polity IV combined democracy scores (Marshall
and Jaggers 2009) amongst members in the first year for which data is available after the
war, on the assumption that, in general, states with similar domestic institutions will
hold similar preferences over foreign policy; the greater the variance in Polity scores, the
more diverse the coalition’s preferences. Given the large number of European wars in
the data, linking Polity scores to what Braumoeller (2012) calls the distribution of ide8
ology is far from inappropriate; in both the 19th and 20th Centuries, democracies and
various forms of autocracy contested the relative sizes of the democratic and either legitimist or Communist communities, making domestic political similarity a workable, if
imperfect, indicator of preference similarity.
Third, as an indicator of the credibility of commitments to sharing the spoils of victory, I measure the percent of pairs of coalition members that share formal alliance commitments in the first year of the war. If, for example, a coalition includes three states and
two of the three possible pairs are allied in the year the war begins, then Percent Allied
equals 2/3; if all three states are allied with one another, then Percent Allied equals one. I
use two versions of the variable, one based on the Alliance Treaty and Obligations Project
(ATOP) data (Leeds et al. 2002), where I consider states allied if they share a defensive,
offensive, or consultation pact, and another based on the Correlates of War data (Gibler
and Sarkees 2004), where I code allies as those sharing a defense pact or an entente.
However, as noted above, expectations over the behavior of a simple measure of alliance
membership are not strong: alliances may signal algined preferences or latent cooperative difficulties that might emerge after the elimination of a common threat. Whether
the effect is to shorten or lengthen the peace between victors will depend, in large part,
on the relative balance of these two types of allies in the sample. Finally, I include several controls—the coalition’s total military capabilities, logged values of battle deaths
and the length of the war in days, as well as an indicator for the Second World War to account for its extreme values on duration, deaths, size, and diversity—all derived from the
Correlates of War data (Sarkees and Wayman 2010, Singer, Bremer and Stuckey 1972).
The full specification of the Cox proportional-hazards (PH) model is
£
¡
¢
¤
h (t |X ) = h(t ) exp (Size) β1 + Diversity β2 + (Percent Allied) β3 + Xβ ,
9
where the hazard function h (t |X ) characterizes the probability that a coalition survives
intact at time t , given that it has survived up to time t , as a function of a set of regressors
and their coefficients. The coefficients β1 -β3 are associated with the three theoretical
variables identified above, and they are accompanied by a vector of control variables
and their coefficeints Xβ. The Cox model makes no assumptions about the underlying or baseline hazard rate, but it does assume that the variables in X have a similar
effect on the probability of survival at any time after victory—that is, that the harzards
are proportional. Following Box-Steffensmeier and Jones (2004, pp. 124-137), I examine the Schoenfeld residuals as a function of time to look for possible violations of the
proportional hazards assumption. I find none, which indicates that the model does not
need to be adjusted for time-varying effects. I turn now to a discussion of the results of
estimating this model on my sample of victorious war coalitions.
Results
Table 1 presents the results of estimating four different versions of the Cox proportionalhazards model, based on each possible combination of alliance measures (ATOP and
COW) and the Second World War dummy variable. Rather than coefficients for each
variable, I present hazard ratios, which indicate the multiplicative effect on the hazard
rate—that is, on the probability that a coalition dissolves at time t —of a one-unit increase in the variable (however scaled). If an increase in a given variable has no effect on
the hazard, then the hazard ratio is 1; accordingly, an increase in the hazard rate (here,
war sooner rather than later) implies a ratio greater than one, while decreases in the
hazard rate (war later rather than sooner) are indicated by a ratio less than one.
Before discussing the theoretical variables, it is worth noting that the direction, magnitude, and statistical significance of all variables are generally robust to both alternate
10
Table 1: Cox PH models of time until coalitional breakdown, 1859-2003
h(t |X )
Variable
Model 1
ATOP
Model 2
ATOP/WWII
Model 3
COW
Model 4
COW/WWII
Theoretical Variables
Size
Diversity
Percent Allied
8.54∗∗
1.20∗∗
1.12∗∗
8.43∗∗
1.20∗∗
1.13∗∗
7.29∗∗
1.17∗∗
1.11∗
6.93∗∗
1.17∗∗
1.11∗∗
0.85∗
1.07
0.44
—
0.85∗
1.15
0.36
0.30
0.88∗
1.10
0.32
—
0.89∗
1.17
0.28
0.39
20/11
-14.77
19.84∗∗∗
20/11
-14.52
20.34∗∗∗
Control Variables
Total Capabilities
Log Battle Deaths
Log War Duration
WWII
Model Statistics
Subjects/failures
Log Likelihood
LR χ2(d.f.)
Significance levels :
20/11
-13.85
21.69∗∗∗
∗ : 10%
∗∗ : 5%
20/11
-13.45
22.49∗∗∗
∗ ∗ ∗ : 1%
11
alliance codings and the inclusion of the World War II dummy variable. Beginning with
the control variables, coalitions that are more powerful in the aggregate appear less
prone to breakdown than weaker coaltions, as indicated by a hazard ratio consistently
les than one; note that this ratio represents the effect of power alone, as two other factors generally correlated with power—size and preference diversity—are also included
in the model. Next, there is no systematic relationship between either the total battle
deaths or the duration of the war and the post-victory durability of the victorious coalition, and despite World War II’s own extreme values in coalition size, diversity, duration,
and severity, its victors are not statistically distinguishable from other coalitions in the
durablity of their own post-war cooperation.7
Turning to the theoretical variables, all three of which are stripped of possible correlation with aggregate military power, each exhibits a hazard ratio greater than one. Thus,
increases in coalitional size, preference diversity, and the percentage of allied members
are each associated with an increased risk of coalitional breakdown. Put differently, coaltions that are larger, more diverse, and with a larger share of allied members will tend to
dissolve into conflict sooner than coalitions that are small, homogeneous, or less composed of allies. In the case of Size, each additional coalition partner—for example, increasing from two to three members—makes a coalition roughly 8.5 times more likely
to break down at a given time. This is effect is substantively large and statistically disernible at p < 0.05; the probability that this relationship is due to chance alone is less
than 5%. This is consistent with Riker’s (1962) size principle, and the relationship holds
up even in the presence of the a measure of preference diversity, which might confound
7
The COW data codes the WWII coalition breaking down with the onset of the Korean War, which ultimately pitted the United States against China. This poses some problems of agency—by the time of the
Korean War, China was controlled by the Chinese Communist Party—but two factors suggest that this is
not an unreasonable coding. First, the United States and Soviet Union did work with the CCP to varying
degrees during the war. Second, North Korea’s invasion of the south occurred with the explicit blessing of
both China and the Soviet Union (Stueck 1995, 2004); the latter was unambiguously a part of the winning
coalition in the previous war.
12
0
Smoothed hazard function
.00005
.0001
.00015
.0002
Figure 1: Hazard of coalitional breakdown by preference diversity, 1859-2003
20000
30000
Low Variance
40000
analysis time
Mean Variance
50000
60000
High Variance
the effects of the size principle itself. However similar their members’ preferences, then,
larger coalitions tend to shed members—violently, in this case—after victory in war.
Next, the hazard ratio on Diversity is greater than one, though the substantive effect
is difficult to assess given the scaling of the variable, whch ranges from zero (the least diverse coalition) to 85 (the most diverse). A one-unit increase in the variance here makes
little sense, so Figure 1 plots the estimated hazard function, which tracks the probability of coalitional breakdown over time as a function of a minimally diverse coalition, a
coalition of average diversity, and a maximally diverse coalition. Beginning with the lowvariance coalition, the probability of war between the victors begins low and increases
only slightly over time, but moving to coalitions of average and sample-maximum diversity, each substantially increases the risk that victorious coalitions will break down
into subsequent conflict. Consistent with Wolford’s (2014b) hypothesis, homogeneous
coalitions—regardless of size or aggregate strength—are uniquely durable compared to
13
0
Smoothed hazard function
.00005
.0001
.00015
.0002
Figure 2: Hazard of coalitional breakdown by percent of states sharing ATOP alliances,
1859-2003
20000
30000
40000
analysis time
25% Allied
50% Allied
50000
60000
100% Allied
their more diverse counterparts. This may be good news for the victors down the line
but potentially bad news for other states that worry about how long the coalition might
stay together and take advantage of its aggregate power.
Finally, an increase in Percent Allied is also associated with a statstically significant
increase in the risk of coalitional breakdown; in this case, the variable ranges from 0 to
100, such that a coalition with 51% of its members allied will be 1.1 times more likely to
break down than a coalition with 50% of its members allied. To get a better sense of the
substantive meaning of the relationship, Figure 2 plots the hazard function for coalitions
that are 25%, 50%, and 100% allied, across which the differences in the hazard are quite
dramatic: coalitions with few allied members are substantially less likely to break down
at a given time than those with even half of their members sharing alliances.
With Diversity capturing the degree of shared preferences in the coalition, Percent
14
Allied captures all those effects of alliances not tied to similar preferences. These remaining effects point to more formally committed coalitions being associated with more
fragile post-victory cooperation. If alliances represent particularly costly forms of commitment (Morrow 1994, 2000), especially relative to informal pledges of cooperation,
then Percent Allied may capture the underlying cooperative problems that necessitated
the formation of the alliance in the first place. It is also possible, as well, that coalitions
with a larger fraction of allies are comparatively more willing to take on partners—as the
Western allies were with respect to the Soviet Union—that will be unreliable after the
war, because the allies expect to be able to work together in defense of the postwar status
quo against unreliable partners. However, the average survival time for non-allied dyads
is roughly 20 thousand days by the COW measure and 19 thousand for ATOP, while the
average survival time for non-allied dyads is roughly 11 thousand and 13 thousand for
COW and ATOP, respetively—suggesting that it is, indeed, allied states who turn against
one another in competition over the spoils of victory.
Conclusion
Roughly half of all victorious war coalitions have seen their members go on to fight one
another in subsequent years, and for some, like the Balkan League in 1913, the time
between victory and intramural war is startlingly short. The empirical analysis above
identifies three features of victorious coaltions that make them uniquely prone to violent
breakdowns in the future: size, diversity of foreign policy preferences, and the extent to
which coalition members were formally allied at the outbreak of war. While the first two
results are consistent with extant predictions about coalitional durability (Riker 1962,
Wolford 2014b), the latter is more surprising. Alliances can bolster general deterrence
(Leeds 2003, Morrow 1994), increase trade (Gowa and Mansfield 1993, 2004, Mansfield
15
and Bronson 1997), as well as provide some degree of control over states that would
otherwise pursue undesirable policies (Morrow 1991, Pressman 2008, Weitsman 2004),
but these benefits may come at the cost of an increased risk of future conflict once allies
eliminate or subdue a common threat on the battlefield.
States often choose their partners in war coalitions under a tight constraint—the desire to win—which leads to compromises over both future shares of the spoils and, as
shown here, future conflicts over those spoils. While the present analysis above explores
only a few pre-war characteristics of coalitions, future work might explore intra-war decisions as well, such as the assignment of geographical areas of responsibility, compensation schemes (i.e., whether partners are rewarded up front or expect to receieve concessions after the war), and perhaps the timing with which members join the coalition
during the war. Each of these factors likely shapes the credibility of commitment to postwar cooperation, perhaps mitigating or exacerbating issues caused by the initial choice
of partner, and uncovering their effects will shed yet further light on the potential downstream problems caused by belligerents’ overriding goal of winning their wars.
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Appendix
Table 2: Victorious Coalitions and their Member States
COW #
War Name
End Year
Coalition
16
Roman Republic
1849
France
Austria
Two Sicilies
22
Crimean
1856
United Kingdom
France
Italy
Turkey
28
Italian Unification
1859
France
Sardinia-Piedmont
46
Second Schleswig-Holstein
1864
Germany
Austria
49
Lopez War
1870
Brazil
Argentina
52
Naval War
1866
Peru
Chile
55
Seven Weeks’ War
1866
Prussia
Mecklenburg Schwerin
Italy
58
Franco-Prussian
1871
Bavaria
Prussia
Baden
Wurttemburg
82
Boxer Rebellion
1900
United States
United Kingdom
France
Russia
Japan
100
First Balkan
1912
Serbia
Greece
Bulgaria
103
Second Balkan
1913
Serbia
Continued on next page
20
Table 2 – Continued from previous page
COW #
War Name
End Year
Coalition
Greece
Romania
Turkey
106
World War I
1918
United Sates
United Kingdom
Belgium
France
Portugal
Italy
Serbia
Greece
Romania
Russia
Japan
107
Estonian Liberation
1920
Estonia
Finland
108
Latvian Liberation
1920
Estonia
Latvia
112
Hungarian Adversaries
1919
Czechoslovakia
Romania
136
Nomonhan War
1939
Soviet Union
Mongolia
139
World War II
1945
United States
Canada
Brazil
United Kingdom
Netherlands
Belgium
France
Poland
Italy
Yugoslavia
Greece
Bulgaria
Romania
Soviet Union
Continued on next page
21
Table 2 – Continued from previous page
COW #
War Name
End Year
Coalition
Norway
Ethiopoia
South Africa
China
Mongolia
Australia
New Zealand
155
Sinai War
1956
United Kingdom
France
Israel
158
Ifni War
1958
France
Spain
186
Angola
1976
Cuba
Angola
187
Second Ogaden, Phase II
1978
Cuba
Ethiopia
211
Gulf War
1991
United States
Canada
United Kingdom
France
Italy
Morocco
Egypt
Syria
Saudi Arabia
Kuwait
Qatar
United Arab Emirates
Oman
221
Kosovo
1999
United States
United Kingdom
Netherlands
France
Germany
Italy
Turkey
Continued on next page
22
Table 2 – Continued from previous page
COW #
War Name
End Year
Coalition
225
Invasion of Afghanistan
2001
United States
Canada
United Kingdom
France
Australia
227
Invasion of Iraq
2003
United States
United Kingdom
Australia
23