Alliances and Conflict, or Conflict and Alliances? Appraising the Causal Effect of Alliances on Conflict

TL;DR

This paper develops an endogenous model of alliances and conflict, revealing that alliances do not necessarily deter or provoke conflict, challenging traditional views on alliance deterrence.

Contribution

It introduces an innovative endogenous theory linking alliance formation and conflict, and employs advanced regression models to identify causal effects.

Findings

Alliances do not significantly deter conflict.

Alliances do not significantly provoke conflict.

Endogenous modeling alters understanding of alliance effects.

Abstract

The deterrent effect of military alliances is well documented and widely accepted. However, such work has typically assumed that alliances are exogenous. This is problematic as alliances may simultaneously influence the probability of conflict and be influenced by the probability of conflict. Failing to account for such endogeneity produces overly simplistic theories of alliance politics and barriers to identifying the causal effect of alliances on conflict. In this manuscript, I propose a solution to this theoretical and empirical modeling challenge. Synthesizing theories of alliance formation and the alliance-conflict relationship, I innovate an endogenous theory of alliances and conflict. I then test this theory using innovative generalized joint regression models that allow me to endogenize alliance formation on the causal path to conflict. Once doing so, I ultimately find that alliances neither deter nor provoke aggression. This has significant implications for our understanding of interstate conflict and alliance politics.