When Boris Yeltsin calls out the tanks and shells parliament, or when he pins medals on veterans, both acts are called executive decrees, but we do not understand both to be equivalent examples of executive discretion over policymaking. Executives increasingly take (or are given) the authority to act without concurrent legislative action. This book offers a theory of political institutions that predicts when executives should turn to decree and when legislatures should accept--or even prefer--this method of making policy. Extensive case studies demonstrate how decree has been used and abused in widely different political environments.