Ratification Patterns and the International Criminal Court

What types of countries have ratified the Rome Statute establishing the International Criminal Court? Because the court relies on state cooperation, it is a good example of a regime facing a "participation problem." In order to be effective, the regime requires active members, but states that fear regime effectiveness will therefore find it potentially costly to join. We analyze the extent to which this problem plagues the ICC. We find that countries for whom compliance is likely to be easiest-democracies with little internal violence-are the most likely countries to join the ICC. On the other hand, countries with the most to fear from ICC prosecution, nondemocracies with weak legal systems and a history of domestic political violence, tend to avoid ratification. We contrast our findings with those of a recent article by Simmons and Danner (2010), arguing that ratification patterns show evidence of credible commitments. Our analysis across a breadth of evidence, both descriptive and multivariate, suggests caution toward arguments about the impact of the ICC on global practices and provides support for the notion that states strategically select themselves into supranational judicial agreements.