One central element of the current war on terrorism is "draining the swamps", addressing conditions within a state that produce international terrorism. This paper empirically examines what factors lead a state to become a "swamp", drawing on a theoretical approach that guides current U.S. policy. This theory looks at the ability of a state to impose costs on terrorist groups within its own borders. The lower the operating costs within a state, the greater the amount of terrorism produced within that state. Using data on the number of international terrorist events originating from a state from 1968 to 1998, an empirical model incorporating variables designed to test this theoretical argument as well as relevant control variables is employed. Strong support was found for the state strength approach, suggesting that one way to address the threat of international terrorism is to strengthen a government's ability to control its own territory.