He ordered a set of changes in counterterrorism procedures, including how the watch list system operates, as well as new efforts to develop more sophisticated explosives detection technology for airport screening checkpoints.

NPR: 'System Failure' In U.S. Screening For Terrorists

Brennan, the president's top counterterrorism advisor, a much broader analysis will be needed -- one that covers the entire homeland security system, is independent of the executive branch, and is bipartisan in the composition of its membership.

CNN: Blame game won't stop terrorism