The head of the National Security Agency told Congress that top-secret surveillance programs - like those leaked recently by former NSA contractor Edward Snowden were key to thwarting terror attacks against the U.S.
Gen. Keith Alexander, the National Security Agency director, said information "gathered from these programs provided government with critical leads to prevent over 50 potential terrorist events in more than 20 countries around the world."
Among those 50 events , according to General Alexander, there were at least 10 "homeland-based threats" including a plot by a Kansas City man to blow up the New York Stock Exchange and a plot to bomb the New York City Subway system in 2009.
But could those plots have been foiled using more traditional methods, or were these surveillance programs truly critical?
Outfront tonight: Democratic Congressman Adam Schiff - he sits on the Intelligence Committee, which held that hearing today at which General Alexander testified.