Regaining presidential prerogatives was high on the new Bush administration's agendafrom the start, but the September 11 tragedy provided the context needed to expand executive authority. U.S. Attorney General John Ashcroft has emerged as a key defender of unilateral presidential power. By examining his and the Justice Department's activities in relation to Congress and the federal courts, this study considers the implications of domestic antiterrorism policies on the constitutional system of divided power. While a preliminary assessment, the study concludes that domestic antiterrorism policies do have a substantial impact on separation of powers.