We don't speak often about the worst of the "what ifs" -- a terrorist attack on the United States that unleashes nuclear, chemical, or biological weapons on our people. John Kerry seems to think that our principal answer to the threat of terrorism is to hire more police, firemen, and emergency medical technicians. But the way to deal with this threat is to preempt it, by destroying the terrorists' ability to attack and to erect defenses against what they may bring against us. That our borders are still porous and that we don't yet have the cooperation of very...