The Transportation Security Administration Secure Flight program has been suspended, supposedly because they have found a number of security vulnerabilities in it. Maybe they are suspending it (for now) because it does not seem to be working - $150 million spent and only lots of unhappy false positive matches (ordinary people who can't fly because they are matched for the wrong reasons). Not a very good benefit-to-cost ratio.

Bruce Schneier has said many things better than I could about how little this program would do to enhance our security.