Washington's defense policy appears to be undergoing significant change as America wages a two-front war on terrorism at home and abroad. The missile defense plan, designed to intercept ballistic missiles from "rogue states," is gaining political support in the current extraordinary situation. There is even talk that tactical nuclear weapons could be used against terrorist organizations. All this is a bad omen for nuclear disarmament.

In the eyes of its critics, the missile defense plan seems to have all but lost its relevance after the Sept. 11 terrorist attacks. Leading members of the Democratic Party, for example, argue that a missile defense system, however sophisticated, could not prevent acts of terrorism, and have urged the Bush administration to give top priority to counterterrorism, rather than building a missile shield of the Star Wars variety.

That is a powerful argument. Terrorists could again hijack commercial airlines and crash them into symbolic targets, as they did in New York and Washington on Sept. 11. They could distribute more mail laced with deadly biological agents such as anthrax. It is also possible, at least in theory, that terrorists posing as air ordinary travelers might bring in tiny nuclear devices concealed in their suitcases. Missile defense is not the answer to such "low-tech" terrorism.