The George W. Bush administration has aggressively advanced claims of presidential supremacy in American government. We use data from surveys to explore the reactions to these claims on the part of three groups of governmental elites and the general public. Responses are shaped by partisanship and ideology, which overwhelm institutional loyalties. Democrats are generally unified in opposing practices that expand presidential power beyond established political or constitutional limits. Republicans are more divided. Some entirely reject those practices. Yet about three quarters of Republicans in all samples endorse presidential supremacy, partially or fully. We consider the implications of the findings for possible longer-term outcomes with respect to these issues.