How national security letters work

How national security letters are supposed to work:

In 1986, Congress first authorized the FBI to obtain electronic records without approval from a judge. Called national security letters, these demands could be used to acquire e-mails, telephone and travel records and financial information, including credit and bank transactions.

The letters could be sent to telephone and Internet access companies, universities, public interest organizations and nearly all libraries, plus financial and credit companies.

Originally the FBI could obtain records only for people suspected of being agents of a foreign power. In 1993, that was expanded to cover records of anyone suspected of communicating with foreign agents about terrorism or espionage.

Finally, the Patriot Act in 2001 eliminated any requirement that the records belong to someone under suspicion. Now any person's records can be obtained if FBI field agents consider the person relevant to a terrorism or spying investigation.