"The detainee provisions passed as part of the National Defense Authorization Act for FY2012 (2012 NDAA; P.L. 112-81), affirm that the Authorization for Use of Military Force (AUMF) in response to the terrorist attacks of September 11, 2001, authorize the detention of persons captured in connection with hostilities. The act provides for the first time a statutory definition of covered persons whose detention is authorized pursuant to the AUMF. During consideration of the detention provision, much of the debate focused on the applicability of this detention authority to U.S. citizens and other persons within the United States. Congress ultimately adopted a Senate amendment to clarify that the provision is not intended to affect any existing law or authorities relating to the detention of U.S. citizens or lawful resident aliens, or any other persons captured or arrested in the United States. This report analyzes the existing law and authority to detain, as 'enemy combatants,' U.S. persons, which, for the purpose of this report means persons who are generally understood to be subject to U.S. territorial jurisdiction or otherwise entitled to constitutional protections; that is, American citizens, resident aliens, and other persons within the United States."
CRS Report for Congress, R42337