THE EMERGING debate over the deployment of U.S missile defenses in Central Europe is based on a series of false pretenses. The Bush administration pretends that it is sensible to invest $225 million next year in preparing to install ground-based interceptors and radar systems in Poland and the Czech Republic to defend against an attack from Iran, even though the glitch-plagued defense system hasn't yet proved workable and Iran doesn't have a missile that could reach the United States or Europe. The Polish and Czech governments, eager to deepen strategic cooperation with the United States, pretend that they will benefit from hosting the systems, even though they have little reason to worry about threats from the Middle East and the Bush administration has been slow to reward their past collaboration in Afghanistan and Iraq.

The prize for cynical posturing, nevertheless, goes to Russia, which in the past few days has suddenly advanced a claim that it knows to be false: that the deployment of the antimissile system would weaken the Russian nuclear deterrent. As Russian President Vladimir Putin and his generals know, even if U.S. interceptors in Poland could function according to the Bush administration's scheme -- which they can't, and won't anytime soon -- they would not be capable of stopping a single Russian intercontinental ballistic missile, much less the massive force that remains at Moscow's disposal. U.S. officials have met with Russian counterparts on at least 10 occasions to explain this.

Mr. Putin and his generals nevertheless are threatening that Russia might respond to the U.S. missile defenses by redeploying intermediate-range missiles that were banned from Europe by a 1987 treaty. An even more sinister comment came Monday from the commander of Russian missile forces, who said that if Poland and the Czech Republic hosted the U.S. rockets and radars, they would be targeted by Russia's strategic missiles. This crude attempt at intimidating Moscow's former Soviet satellites predictably produced a defiant response from the two governments and probably eliminated any domestic opposition to an otherwise questionable venture. As Czech Foreign Minister Karel Schwarzenberg put it, "The Czechs will now think the shield is even more necessary."

The Bush administration's pushing of this initiative, which would not result in the deployment of any interceptors in Europe before 2010, is probably motivated by the same political impulses that have driven missile defense since 2001. Administration officials are determined to create a program so literally set in concrete that it can't be stopped or reversed by future presidents -- as was the missile defense program of President George H.W. Bush. Whether the technology actually works or a threat exists that justifies the rush never seems to matter much.

Such sandbagging justifies close scrutiny by Congress of the Pentagon's $10 billion funding request for missile defense in next year's budget, including the funds for Poland and the Czech Republic. But the Russian gamesmanship is more worrisome. On the opposite page today, Mr. Putin's foreign minister denies any interest in confrontation. But at the same time Mr. Putin may use the U.S. defense program as an excuse to revive a major piece of the Soviet nuclear arsenal with which to threaten NATO members in Europe. It's hard to think of a quicker way to revive the Cold War.