At airports throughout the United States, we have deployed additional airport law enforcement officials, behavior-detection officers, air marshals, and explosive-detection canine teams, among other security measures, both seen and unseen.
Like many suspected al-Qaeda operatives, he was able to exploit the region's lax law enforcement and porous borders to move around and avoid detection.
Chemical and biological sensors already in place on the National Mall will be supplemented with radiological detection equipment, including radiation pagers on the belts of some law enforcement officers.