The Foreign Intelligence Surveillance Court released its first public explanation for why it is allowing the US government to collect phone records of Americans.
The now declassified opinion from the federal court says FISA, the Foreign Intelligence Surveillance Act, which orders telephone companies to hand over bulk records of its customers, does not violate the Constitution's Fourth Amendment or privacy rights.
Those phone companies include Verizon, T-Mobile US, AT&T, and Sprint.
According to the Washington Post, the National Security Agency program gathers records of the time and length of the phone calls but not subscriber names or their content.
Court Judge Claire Eagan asked her August 29 opinion be made public "because of the public interest in this matter." The court released the opinion Tuesday although portions were blacked out.
The 29-page opinion is an attempt to address broad criticism of the surveillance collection program which was first disclosed in June by former NSA contractor Edward Snowden.
FISA, the Foreign Intelligence Surveillance Act, a program of the Bush administration allows the government to eavesdrop without a warrant on Americans' phone calls if one of the parties is believed to be outside the US.
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The government says the program was authorized by the court in 2006 under Section 215 of the Patriot Act, information Snowden made public.