National Security Letters: Circumventing the Warrant Requirement or Legitimate Law Enforcement Tool?

National Security Letters (NSLs) are a type of administrative subpoena issued by the FBI used in terrorism and espionage investigations. They are used to obtain subscriber and transactions information from third-parties (communications providers, financial institutions, and consumer credit agencies).

Since the attacks on September 11th and subsequent enactment of the Patriot Act, the use of NSLs by the intelligence community has been on the rise. In 2000, there were 8,500 requests. That number ballooned to 49,000 in 2006.

NSLs have been the subject of debate in the legal community on both constitutional grounds and the methods in which they are administered. There have been challenges to the constitutionality of NSLs and, as a result, amendments to the legislation authorizing their use. The use of NSLs and the debate surrounding them continue to evolve.

An NSL vs. a search warrant

A search warrant is only granted after a showing of probable cause before a neutral magistrate. There is no such requirement for a NSL. Moreover, the subject of the search is never informed of the investigation. Finally, the scope of the search can be broader under a search warrant than under an NSL.

Types of NSL

There are five types of NSL. The first two were created in 1986: under the Electronics Communications Privacy Act and the Right to Financial Privacy Act. The third and fourth types were created in the mid-90s: one under the Fair Credit Reporting Act, the other under the National Security Act. The fifth type was also authorized under the National Security Act.[1]


The Patriot Act did not create NSLs, but expanded their scope. Under the Patriot Act, Congress changed the standard under which an NSL may be issued from “specific and articulable facts giving reason to believe” to merely “relevant.” Not surprisingly, as a result of this expansion, the use of NSLs has grown exponentially. This overbroad authority and pervasive practice infringes on the privacy rights of innocent citizens. Through NSLs, the FBI is able to collect massive amounts of data on ordinary citizens with no links to terrorism.

Proponents of NSLs argue that they are used only during the course of a duly authorized national investigation. NSLs are vital to the FBI’s ability to investigate a subject without tipping off the subject, as the presentation of a search warrant would. The information NSL allow the FBI to obtain are basic information about the subjects, their finances and who they are interacting with. The information obtained from NSLs is limited and the Supreme Court has ruled that information is not constitutionally protected[2]. NSL were used as a part of every significant national security investigation.

A troubling aspect of NSLs are the “gag” orders. NSLs generally contain language informing recipients that they are not permitted to inform the subject about the NSL or what was requested. After successful legal challenges on First and Fourth Amendment grounds[3], Congress amended the law to allow recipients to challenge NSLs. Moreover, it required the FBI to prove that disclosure of an NSL would harm a national security case.

There are also concerns about how these NSLs are administered. Three Department of Justice IG reports found misuse and mismanagement. There is also a lack of independent oversight.

Proponents argue that, although there have been internal controls breaches, most of the errors discovered were non-substantive, and there were no instances of intentional misuse. Morever, the FBI continues to examine, evaluate and improve its policies and procedures the FBI employees must follow to mitigate risk. There are training requirements for all FBI employees. They point out that all NSLs must be approved by a high-level FBI official. Finally, proponents argue that the ethical requirements of an FBI attorney responsible for approving an NSL act as an effective internal control.


[2] United States v. Miller, 307 U.S. 174 (1976)

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