James Clapper, the director of national intelligence, released a statement on Monday in which he announced that he authorized the release of numerous internal National Security Agency documents, including training slides and “internal guidance,” which he said describe the legal basis for the secretive agency’s mass surveillance, or foreign intelligence data collection programs, as authorized by Section 501 and 702 of the Foreign Intelligence Surveillance Act.

According to the statement, the declassified documents also include the United States Signals Intelligence Directive 18, which details the policies, procedures and lengths to which the NSA says it goes to make sure its foreign intelligence data collection efforts are constitutional.

At issue is XKEYSCORE, the NSA bulk electronic communications metadata collection program that was revealed and confirmed by former government contractor and whistle-blower Edward Snowden. He is now living in Russia under temporary asylum and fighting extradition to the U.S., which considers him a fugitive, on charges of espionage and theft of government property.

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