I believe our intelligence and anti-terrorism efforts were equally as effective before 9/11 when we obeyed the Constitution profusely. None of the alleged tactics we take today in addition to Constitutional methods are more effective than our normal investigative practices. Except for inside jobs, our anti-terrorism agencies have very effectively prevented terror actions in America by following the Constitution and Bill of Rights' mandates.

What we do not have is an introspective intelligence agency to at least post-humously investigate and solve inside attacks, or even prevent them.