The presidency was designed to have limited power, suspended in a series of checks and balances. But executive authority expanded dramatically over time. It took the presidential excesses of Vietnam and Watergate to prompt a legislative resurgence, a sequence bookended by Arthur M. Schlesinger, Jr.'s The Imperial Presidency and James Sundquist's The Decline and Resurgence of Congress. Yet even before September 11, assertive presidents and fragmented Congresses had allowed the presidency to regain much of the initiative lost in the 1970s; and in the global war on terror, a “new” imperial presidency has been cemented, grounded in broad claims to a “unitary” executive branch. Will there be another legislative resurgence in response? The question goes to the legitimacy of representative government's responses to the crises that already define the twenty-first century.