Memorandum for Alberto R. Gonzales, Counsel to the President, and William J. Haynes, II, General Counsel, Department of Defense: Re: Authority for Use of Military Force to Combat Terrorist Activities Within the United States [October 23, 2001] [open pdf - 6MB]
This opinion from the Justice Department's Office of Legal Counsel addresses the use of U.S. military forces in counterterrorism operations on U.S. soil. "You have asked for our Office's views on the authority for the use of military force to prevent or deter terrorist activity inside the United States. Specifically, you have asked whether the Posse Comitatus Act, 18 U.S.C. § 1385 (1994), limits the ability of the President to engage the military domestically, and what constitutional standards apply to its use. We conclude that the President has ample constitutional and statutory authority to deploy the military against international or foreign terrorists operating within the United States. We further believe that the use of such military force generally is consistent with constitutional standards, and that it need not follow the exact procedures that govem law enforcement operations."
U.S. Dept. of Justice: http://www.justice.gov/