(OpEd) WASHINGTON -- Proponents of national missile defense are urging President-elect George W. Bush to move quickly to deploy a system to protect the United States against potential ballistic missile attacks from Iraq, Iran, North Korea, and China. They argue that he will be making a major mistake if he lets his administration subject missile defense to a lengthy policy review. It will give opponents time to organize and inevitably entangle the issue in the 2002 congressional elections. Instead of waiting, they conclude, Mr. Bush should seize the moment. This assessment may tempt the new president. Mr. Bush could move quickly and adopt the Clinton administration's missile defense deployment schedule, which proposes beginning construction of a key radar in Alaska next year. If Moscow refused to revise the Anti Ballistic Missile Treaty to permit a nationwide defense, the United States could then withdraw from the treaty. Although a momentous step, President Bush could argue that he was merely following Bill Clinton's lead. By making deployment seem inevitable, Mr. Bush might overwhelm the domestic political opposition in the short term.

But from a longer term perspective, rapid deployment is a bad idea. It could leave the United States with a mediocre missile defense, strained relations with most European allies, and major problems with Moscow - not to mention Beijing. American national security could suffer, particularly if a brusque defensive deployment led Moscow to terminate bilateral programs to secure its frighteningly dilapidated inventory of nuclear warheads and materials. Such an outcome would eventually fracture whatever domestic political support for missile defense the Bush administration had enjoyed. Rather than moving quickly on missile defense, Mr. Bush should move sensibly.

He should remain unwavering in his commitment to defending the United States. But he does not need to commit immediately to a specific technology, or to take steps that would violate the ABM Treaty until 2002, or perhaps even 2003. He has time to proceed deliberately for four reasons:

• The threat is limited. Only Russia and China currently threaten the United States with long-range missiles, and both could almost surely counter any defense now on the drawing boards. The threat from North Korea, Iran, and Iraq is still probably several years off, or even longer.
   

• The Pentagon needs time to research other technologies. The Clinton administration focused its efforts on developing a system to shoot down warheads in space. That poses a daunting technological challenge, witness the system's two recent test failures. The Pentagon has not adequately investigated other technologies, most notably boost-phase interceptors. These would shoot down enemy missiles before they reached space, when they were easy to locate and when they presented large targets. Besides being less technologically challenging than a Clinton-style system, boost-phase defenses are also far less vulnerable to countermeasures. Boost-phase defenses based on land, sea, or in the air are also less likely to provoke Moscow. They must be based within a few hundred miles of the enemy missile launch point; hence, they cannot shoot down missiles launched from deep in Russia's interior.
   

• The Bush administration needs time to negotiate changes to the ABM Treaty. Persuading Moscow to revise that 1972 treaty to permit nationwide missile defense is far preferable to abandoning it. Withdrawal would harm U.S.-Russian relations - especially efforts to reduce offensive nuclear arms in both countries.