International Military Alliances, 1648-2008 - Douglas M. Gibler

Introduction: Research and Methodology

and Levy (1981), among others, have clearly shown that many
alliances are not followed by war. The presence of these peaceful
alliances makes it difficult to come to any definitive conclusions
on alliances as a correlate of war.

Conceptualizing Alliances

One major reason for the lack of conclusive evidence regarding
the relationship between alliances and war is the lack of proper
conceptualization. For example, almost all the studies that use
the Correlates of War data have grouped many different types of
alliances as similar cases. This groups the Hitler-Stalin pact
(1939) together with peace settlements that settled major wars,
like the Quadruple Alliance of 1815 signed during the Congress
of Vienna. As with these two cases, the effects of most alliances
are of course going to be dependent on the intentions of the
leaders making the alliances. The difficulty, however, rests in
determining the intentions these leaders had when the alliances
were formed.
Although some scholars have concentrated on the actual
terms of the alliances for differentiating across alliance types
(see Singer and Small 1966; Leeds et al. 2002), a more funda-
mental way of understanding leader intentions comes with a
quick look at some simple characteristics of the states that sign
an alliance. Alliances can be formed with almost any type of
state in the international system; thus, important information
can be found in the types of states that a leader chooses for
allies. Think of it this way: if a leader chooses to ally with a state
of lesser power, that leader is probably not interested in using
the alliance to aggregate the power of the states against a com-
mon foe. Similarly, if a leader chooses to ally with a state with
foreign policies that have differed from the leader’s policies, it
would be unlikely that the leader expects to trust the ally

enough to fight together in defense. Figure 1 puts these two core

concepts—interests and capabilities—together in tabular form.

Group A, the category of extended deterrence alliances, con-

sists of alliances dominated by one state in a bilateral alliance or

by a few states in a multilateral alliance. General agreement

among alliance members suggests that these asymmetric

alliances are likely to be vehicles of extended deterrence. The

smaller states gain security against rivals or possible predatory

major states, but because the smaller states already agree with

the policy position of the major state, the major state is likely to

gain few tangible benefits in the exchange. Intangible benefits

then become the focus of the alliance for the major state and

include such things as war avoidance, protection of similar

interests, and perhaps the ability to foster even more agreement

in smaller alliance partners.

The North Atlantic Treaty Organization (NATO), established

in 1949, is one of the prime examples of this type of alliance. On

average, alliance members generally agree on major policy ini-

tiatives; however, this particular alliance continues to be domi-

nated by the United States. During the cold war, Western

Europe received increased security benefits against possible

Soviet aggression, and the United States maintained the ability

to have some say in European politics as part of preserving the

peace. Calls for expansion of NATO emphasize the ability of the

alliance to provide security for smaller states as they democra-

tize and become more “Western” in their interests (Gibler 1999;

Gibler and Sewell 2006).

Group B alliances, imposed alliances, differ from NATO and

other alliances with shared similar interests because the interal-

liance level of agreement is not high. This low level of agree-

ment obviously makes it difficult for these alliances to form, but

if they do form, they are likely to offer the major state tangible

benefits in return for the provision of security. Tangible benefits

are likely to include the provision of military bases, oil, or

liii

FIGURE 1 How Interests and Capabilities Combine in an Alliance

Extended deterrence alliances Capability-aggregating alliances

Imposed alliances Single issue alliances