In the immediate aftermath of the attacks of September 11, 2001, in an atmosphere of fear and uncertainty, the U.S. Congress passed an Authorization for the Use of Military Force (AUMF) that was unmoored from American traditions. The 2001 AUMF is unique among other such authorizations in American history in that it includes no limitations in time, geography,
operations, or a named enemy, as this report documents in detail. (…)

A realistic window of opportunity is emerging to refine the law by bringing it in line with historical practice and putting it on the course toward repeal. The war in Afghanistan is
coming to a close. The campaign to degrade and destroy core al-Qaeda has largely succeeded, rendering the organization “probably unable to carry out complex, large-scale attacks in the West.” Moreover, the expansion of operations under the AUMF has already stressed its authority to the limits and leaves open the possibility of expansive interpretations of the law
by future administrations, further calling for refinement.

This paper assesses the national security risks of perpetual warfare entailed by the 2001 law and recommends a way forward to realize President Obama’s commitment to “refine, and
ultimately repeal” 2 the AUMF.