National security letters are administrative subpoenas that allow the FBI to demand non-content records—such as phone numbers dialed, transactional data, and subscriber information—without prior judicial approval. Section 505 of the USA PATRIOT Act, enacted in 2001, broadened their use to information deemed “relevant” to authorized terrorism or counterintelligence investigations and expanded approval authority to special agents in charge of the FBI’s 56 field offices. Recipients generally received nondisclosure orders, preventing them from revealing even that the government had made a demand.
The system faced major legal and oversight challenges. Nicholas Merrill, founder of Calyx Internet Access, sued after receiving an NSL; in September 2004, a federal district judge found the regime violated the Fourth and First Amendments, though the ruling was stayed. A 2007 report said a Justice Department audit found more than 1,000 FBI rule violations in a sample covering 10% of national-security investigations from 2002 through 2007. Congress added judicial-review and disclosure safeguards in 2006, and the Second Circuit upheld a constitutionally constrained nondisclosure regime in 2008. In 2015, a federal court lifted Merrill’s gag order, allowing him to publicly discuss the NSL. A 2014 Justice Department Inspector General report said the FBI had subsequently corrected its practices.
