Reshaping the International Order: How Does War Affect Alliances?

• In Event: Alliance Politics

Abstract

From the Athenian effort to peel Melos away from Sparta to Napoleon’s use of war to disrupt enemy coalitions and build his own to Putin’s expectations that invading Ukraine would weaken NATO, leaders throughout history have seen war as a means of shaping international alliances to their liking. At times, as with the international order that the United States constructed after World War II, this effort is successful; in other cases it backfires, as war participants lose allies or see adversaries grow closer. How does interstate war affect the international alliance structure? Surprisingly little work has examined this question explicitly. We identify four key propositions from existing theories: that aggression and growing power will provoke counterbalancing coalitions; that war victors can reshape international order in their favor; that more democratic regimes will be more effective at building alliances after war; and that the reshaping of state preferences through regime change and the resolution of outstanding disagreements facilitates the creation of new alliances. We test these claims statistically through analyses of changing alliance structures after Correlates of War interstate wars. Preliminary analysis finds support for predictions that victorious and democratic countries are most likely to improve alliance relations through war.

Authors

• Alex Weisiger, University of Pennsylvania

• Paul Silva, University of Pennsylvania