The U.S. government "kill[s] people based on metadata," but it doesn't do that with the trove of information collected on American communications, according to former head of the National Security Agency Gen. Michael Hayden.

The U.S. government "kill[s] people based on metadata," but it doesn't do that with the trove of information collected on American communications, according to former head of the National Security Agency Gen. Michael Hayden.