US Presidents have long issued presidential directives to federal agencies to adopt and implement programs to advance presidential priorities, both pursuant to statutes passed by Congress and outside of them. Federal courts from the first presidency established their power of judicial review of such directives, but they have not always exercised that prerogative to restrict wide-ranging assertions of executive power. This examination of judicial decisions analyzes the evolution of federal judicial treatment of presidential directives and the legal bases and principles employed in federal court decisions. This Element assesses the degree to which such decisions have been restrictive or supportive of such presidential directives. A more recent trend toward more restrictive principles is illuminated. Finally, implications for presidential, congressional, and federal agency policymaking are discussed.