By Justin Elliott, ProPublica
In defending the NSA's sweeping collection of Americans' phone call records, Obama administration officials have repeatedly pointed out how it could have helped thwart the 9/11 attacks: If only the surveillance program been in place before Sept. 11, 2001, U.S. authorities would have been able to identify one of the future hijackers who was living in San Diego.
Last weekend, former Vice President Dick Cheney invoked the same argument.
It is impossible to know for certain whether screening phone records would have stopped the attacks -- the program didn't exist at the time. It's also not clear whether the program would have given the NSA abilities it didn't already possess with respect to the case. Details of the current program and as well as NSA's role in intelligence gathering around the 9/11 plots remain secret.
But one thing we do know: Those making the argument have ignored a key aspect of historical record.
U.S. intelligence agencies knew the identity of the hijacker in question, Saudi national Khalid al Mihdhar, long before 9/11 and had the ability find him, but they failed to do so.
"There were plenty of opportunities without having to rely on this metadata system for the FBI and intelligence agencies to have located Mihdhar," says former Senator Bob Graham, the Florida Democrat who extensively investigated 9/11 as chairman of the Senate's intelligence committee.