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INTRODUCTION
The literature on intergovernmental organizations (IGOs) and conflict has
burgeoned over the last two decades. This is not surprising when one considers the rapid
increase of IGO actions in conflict around the globe. The overwhelming majority of this
literature has focused on the most powerful IGO of all, the United Nations, and its
peacekeeping role in mitigating civil conflict. However, in addition to the important
contributions of the UN, IGOs as geographically varied as the North Atlantic Treaty
Organization, the Organization of American States, the Organization of African Unity,
and the Arab League have taken action in a number of diverse conflicts. The conflicts
which are the targets of action also often occur between, rather than within, states in the
international system. Indeed, the frequency of IGO action in interstate conflict rivals that
for civil conflict. For example, while the UN sent peacekeeping missions to 32 percent
of civil wars in the post-cold war period (Gilligan and Stedman; 2003), various IGOs
took low and high- level actions in approximately 30 percent international militarized
disputes in the 1984 to 1994 period.
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Yet, surprisingly, the literature on why and when diverse intergovernmental
organizations should be likely to participate in conflicts between states is very limited.
While no literature systematically tests why IGOs should take action in international
conflict, a variety of theoretical perspectives suggest some promising avenues for
exploration. Liberals theorists, for example, suggest both that a similarity of democratic
institutions leads to reduced conflict (Maoz and Russett; 1993, Dixon; 1994, Russett and
Oneal; 2001) and that IGOs endeavor to promote democratic norms (Andersson; 2001,
Shannon; 2005). Consequently, one might expect that institutional format should help
explain IGO action. In a similar vein, power transition theory hypothesizes that states
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Gilligan and Stedman (2003) note that during the cold war, the UN only launched missions in six percent
of civil wars.
Convention