If President George W. Bush’s budget requests are met, the United States will spend more this year than it ever has on antiballistic missile defense—some $12 billion, or nearly three times what the United States spent on antimissile systems during any year of the Cold War. The United States would spend more than $60 billion on missile defense in the next six years, an unprecedented sum, even for the Pentagon. But what makes this spending most remarkable is that the threat it seeks to counter is actually declining. There are far fewer missiles, missile programs, and hostile states with missiles aimed at the United States and its armed forces than there were 20 years ago. The number of long-range missiles fielded by China and Russia has decreased 71 percent since 1987. The number of medium-range ballistic missiles pointed at U.S. allies in Europe and Asia has fallen 80 percent. Most of the 28 countries that have any ballistic missiles at all have only short-range Scud missiles—which travel less than 300 miles and are growing older and less reliable each day. Even the number of countries trying to develop ballistic missiles is falling.

This is not to say that our world is without risks. Russia has more than 660 missiles capable of striking the United States. China has about 20. But these weapons are not the focus of the United States’ antimissile program. In fact, U.S. officials have gone out of their way to assure Russia that the antimissile bases they seek to build in the Czech Republic and Poland are not intended to offset the Kremlin. They can’t. There are countermeasures both the Russians and the Chinese can put on their missiles that would render any interceptor ineffective. Instead, the United States justifies the antiballistic missile program by the alleged threat from Iran. Of the $60...