For nearly three decades, the Anti-Ballistic Missile Treaty has been the cornerstone of international arms control. The logic of deterrence created a situation where nuclear powers held their adversaries' populations hostage; an antiballistic missile system eroded the certainty of mutually assured destruction. U.S. President George W. Bush now says that he will push through with plans to build a missile defense program. But an arms race would only undermine the promise of national defense under an ABM shield. Such a race is not inevitable, but heading it off will require coordination that the Bush team has shown little inclination to pursue.

During the campaign, then-candidate Bush promised to deploy an antimissile system that would detect and shoot down a limited number of ballistic missiles -- either those launched accidentally or by a "rogue nation," such as North Korea or Iraq. Mr. Bush and other missile defense supporters are undaunted by the estimated cost of the system, its impact on strategic stability and even doubts about its efficacy. They remain steadfast in their commitment to deployment and certain about the security such a system will reportedly yield.

The drumbeat has grown in recent weeks. Unnamed administration officials have been preparing the ground for a presidential declaration. Last week, Mr. Lucas Fischer, deputy assistant secretary of state for strategic affairs, told the Danish Parliament that the U.S. "will deploy defenses as soon as possible; therefore, we believe that the ABM treaty will have to be replaced, eliminated or changed in a fundamental way."