"Americans first learned about the telephone metadata program that appellants now challenge on June 5, 2013, when the British newspaper The Guardian published a FISC order leaked by former government contractor Edward Snowden," the court noted.

The order directed Verizon to produce to the NSA "on an ongoing daily basis ... all call detail records or 'telephony metadata' created by Verizon for communications (i) between the United States and abroad; or (ii) wholly within the United States, including local telephone calls."

The US government justified the program by saying that it was covered under Section 215 of the USA Patriot Act, which was signed into law by President George W. Bush on October 26, 2001, after the terrorist attacks of 9/11.