CollegeScholars, the courts, and the public have been ambivalent about prerogative, the power of presidents to take extraordinary actions without explicit legal authorization in emergencies, because it seems to defy core principles of liberal constitutionalism. This article examines the relation between prerogative and liberal constitutionalism by comparing the approaches of two Founders with different conceptions of executive power, Jefferson and Hamilton. Although they both endorsed a Lockean conception of prerogative that makes it possible to secure vital substantive ends that might be imperiled by strict adherence to ordinary legal forms in an emergency, they disagreed over the constitutionality of prerogative. Whereas Hamilton located the authority for prerogative within the implied powers of the Constitution, Jefferson expected presidents to admit wrongdoing and seek post-hoc approval from the public, a difference with important implications for both democracy and constitutional practice that can be traced back to ambiguities in Locke's theory of prerogative.