Existing theories of legislative delegation to bureaucracies typically focus on a single legislature, often the U.S. Congress. We argue that this parochial focus has important limitations. If one contends that politicians respond rationally to their political environment when adopting strategies for controlling bureaucrats, then theories of control should be able to explain how differences in the political environment-and in particular in the democratic institutional arrangements that shape this environment-influence strategies for controlling bureaucrats. We offer such a theory about the conditions under which legislatures should rely on statutory control (i.e., detailed legislation) in order to limit the discretion of agencies, The theory focuses on the interactions of four factors: conflict between legislators and bureaucrats, the bargaining costs associated with choosing the institutions for controlling bureaucrats, the professional capacity of legislators to create institutions for control, and the impact of political institutions on the relative costs and benefits of statutory and nonstatutory strategies of control. We test our argument using legislation from 1995 and 1996 that affects Medicaid programs. The results show that legislatures are more likely to make use of statutory controls when control of government is divided between the two parties, the two chambers of the legislature are unified in their opposition to the executive, the legislature is more professionalized, and the legislature does not have easily available options for nonstatutory control.