On May 6, 2004 [OLC Lawyers] "Goldsmith and Philbin completed an OLC legal memorandum assessing the legality of the PSP as it was operating at that time...The OLC memorandum stated that the Authorization for Use of Military Force (AUMF) passed by Congress shortly after the attacks of September 11, 2001 gave the President authority to use both domestically and abroad 'all necessary and appropriate force,' including signals intelligence capabilities, to prevent future acts of international terrorism against the United States."