Since 9/11, legislators and commentators alike have hailed expiration dates—or “sunset provisions”—as a means to moderate the government’s tendency to curtail individual freedoms in response to security crises. Sunsets advocates explain that such provisions provide Congress with an opportunity to reevaluate counterterrorism legislation after the crisis atmosphere has passed, enabling legislators to adjust any policy whose infringement on civil liberties appears, in retrospect, unjustified by its benefits.

This Article demonstrates that, rather than guarding against the longterm entrenchment of overly robust security measures, sunsets have the opposite effect. The Article begins by illustrating that Congress’s high expectations for counterterrorism sunsets have not been borne out by their impact. It then explains that the failure of sunsets to prompt meaningful reevaluation of post-crisis counterterrorism measures stems from two sources. First, optimism over sunsets’ potential relies on several inaccurate assumptions about how the state of the world will change between the time a statute is enacted and its sunset date. And second, this optimism fails to account for the President’s outsized role in counterterrorism policymaking. Finally, the Article identifies sunsets’ hidden cost: paradoxically, by insisting on including sunset provisions, legislators concerned about overzealous counterterrorism legislation actually facilitate the enactment of such statutes. And as sunsets do not subsequently correct overzealous policy, they enable the long-term entrenchment of the very policymaking errors they are designed to prevent. The Article concludes that citizens and legislators concerned about the civil liberties costs of counterterrorism policy should reject claims that sunsets are an effective answer to those concerns.