Three years and eight months after the terrorist attacks that changed our lives and after spending $4.5 billion on screening devices to monitor airports, seaports, mail and the air we breathe, the Department of Homeland Security has acknowledged what many of us frequent fliers already suspected. The money was misspent on equipment that has failed to do the job. As with most things governmental, failure does not mean having to try something else. It means spending more money on even more expensive equipment. Among the problems associated with the current equipment, as detailed in last Sunday's New York Times, are...