Abstract: | Foreign aid is usually seen as a form of international cooperation. Thus, the expectation is that states engaged in international rivalry with one another should be unlikely to provide each other aid. However, they do provide their enemies aid. We consider how situations of uncertainty influence aid transfers between states. We argue that states may provide each other aid to limit uncertainty from potential regime changes that could lead to war. Such uncertainty is particularly bad for rivals who are prone to militarized conflict. We find that rivals may provide one another foreign aid when one of the countries is experiencing regime-threatening levels of domestic instability. We compare these results to the behavior of nonrivals and find that: Rivals are likely to provide their enemies aid in times of uncertainty; rivals are no less likely to give aid to each other than are nonrivals; and rivals provide more aid during times of instability than do nonrivals. |