ABSTRACT
For nearly 30 years, national security letters (NSLs) have served intelligence agencies as a powerful tool for collecting information. Although the initial NSL statute created a weak and often ineffective means of requesting information from financial institutions, NSL powers and authorities have developed over the years to become a vital component in the conduct of successful counterintelligence and terrorism investigations – described by some FBI personnel as “our bread and butter.”1 The information gathered through NSL requests often provides essential evidence that is required to obtain more invasive tools for intelligence gathering such as wiretaps, pen register/trap and trace devices, and search warrants. Given the potential for abuse in using these tools to gather highly personal information, Congress has sought to balance the investigative needs of intelligence agencies with the legitimate privacy and civil liberty interests of the individuals against whom these powers are used.
