Senators Challenge Claim NSA Surveillance Stopped Terrorist Attacks

Where's the evidence?

During a cybersecurity hearing yesterday in the Senate, NSA boss General Keith Alexander was asked a bunch of questions about the NSA surveillance scandal. At one point, he claimed that he didn't have an exact number of cases in which the dragnet of information collected had stopped terrorist activity, but that it was "dozens" and that he would provide more info in a classified session (held today). However, Senators Ron Wyden and Mark Udall -- both on the Senate Intelligence Committee, and both paying close attention to these issues -- have put out a statement today saying that they've seen no evidence of this and they'd like General Alexander to clarify.