Terrorist attacks on democracies have awful but predictable effects: they trigger public panic and lead politicians to pass restrictive laws with the promise of greater security. In this brilliant study, a Yale legal scholar outlines proposals aimed to prevent the abuses of presidential power that could all too easily result from a future attack. Ackerman thinks that the United States panicked in the aftermath of 9/11 and rushed the Patriot Act into law. In the event of a large-scale nuclear or biological terrorist attack, waves of repressive legislation would follow -- a "pathological political cycle" that could prove devastating to civil liberties. In the age of terrorism, Ackerman argues, American democracy must, in effect, tie itself to the mast by creating in advance delimited emergency powers with requirements for repeated congressional authorization and specific time limits. This "emergency constitution" would give the government short-term powers to prevent a second strike but guard against the panic-driven abolition of cherished liberties. Building on constitutional principles of checks and balances, the book details institutions and principles that would inform such an emergency act. Such future contingencies are grim, but the continuing relevance of the foundational principles Ackerman uses to guide his analysis is heartening.