Debate over the National Security Agency's collection of telephone metadata is taking a dangerous turn. There's a risk that Congress or the White House will impose ill-considered constraints on the NSA that would compromise our ability to protect the United States against the next 9/11.
The metadata acquired in this program doesn't reveal the content of anyone's phone calls — just the records of which numbers have dialed which numbers and when. This is transactional information that phone companies compile for billing purposes, and the Fourth Amendment does not require a warrant supported by probable cause to obtain these records.
At least 14 federal judges have approved the NSA's acquisition of this data every 90 days since 2006 under the business records provision of the Foreign Intelligence Surveillance Act (FISA).