National Security Letters in Foreign Intelligence Investigations: Legal Background and Recent Amendments [Updated March 28,2008] [open pdf - 231KB]
"Five federal statutes authorize intelligence officials to request certain business record information in connection with national security investigations. The authority to issue these national security letters (NSLs) is comparable to the authority to issue administrative subpoenas. The USA PATRIOT Act expanded the authority under four of the NSL statutes and created the fifth. Thereafter, the authority has been reported to have been widely used. Prospects of its continued use dimmed, however, after two lower federal courts held the lack of judicial review and the absolute confidentiality requirements in one of the statutes rendered it constitutionally suspect. The USA PATRIOT Improvement and Reauthorization Act (H.R. 3199), P.L. 109-177, and its companion P.L. 109-178, amended the five NSL sections to expressly provide for judicial review of both the NSLs and the confidentiality requirements that attend them. The sections have also been made explicitly judicially enforceable and sanctions recognized for failure to comply with an NSL request or to breach NSL confidentiality requirements with the intent to obstruct justice. The use of the authority has been made subject to greater Congressional oversight."
CRS Report for Congress, RL33320