In Terror in the Balance, Posner and Vermeule take on civil libertarians of both the left and the right, arguing that the government should be given wide latitude to adjust policy and liberties in the times of emergency. They emphasize the virtues of unilateral executive actions and argue for making extensive powers available to the executive as warranted. The judiciary should neither second-guess security policy nor interfere on constitutional grounds. In order to protect citizens, government can and should use any legal instrument that is warranted under ordinary cost-benefit...