Far more effective, given the lessons of history, as I've observed before, is tracking the patterns of behavior that generally match up with terrorist activity: "associates and educational history and family ties and travel history," etc.
The Obama administration is set to announce new screening protocols for international flights, replacing the systematic extra screening for residents of 14 largely Muslim countries instituted after the attempted Christmas bombing. "The new security protocols will be built around present-day threat situations," officials tell the Times, "where fragments of intelligence from various threat streams are considered." This more responsive and cooperative system will crosscheck recent travel histories and personal info with recent reports, "So, for example, if terrorist groups are recruiting college-age men who have spent time in Asia and have been to the Middle East, that type of travel pattern would raise a flag to officials at international airports," in the Times's (justifiably) supportive hypothetical. Call it "intelligent profiling," maybe?
I hope we have senate hearings about this, so that national security conservatives can do backflips trying to explain why the pragmatic proposals of the national security establishment should not be deferred to in this case, just like with Don't Ask Don't Tell.