Bilateral flows of international migrants exhibit tremendous variance both across destination countries and over time. To explain this variance, studies of international migration tend to focus on economic determinants such as income differentials or on social conditions such as the presence of coethnics in certain destination countries. The authors argue that migration is driven not solely by economic or social determinants; rather, the political environment across destinations plays a substantively large role in influencing bilateral migration flows. They test the importance of the political environment—citizenship rights and the prominence of right-wing parties—using data on migration flows from 178 origin countries into 18 destination countries over the period 1980–2006. They find, even after controlling for a variety of economic, social, policy, and international variables, that variation in political environments across time and destination plays a key role in observed patterns of international migration.