by Sanford Gottlieb

Even as he was telling Iran not to produce nuclear weapons, President Bush was urging Congress to pay for a new nuclear weapon designed to destroy underground military facilities.

Although the nuclear "bunker-buster" is still on the drawing board, Iran can be expected to charge the United States with atomic hypocrisy during the current war of words.

No less than a conservative Republican from Ohio, Rep. David L. Hobson, has thwarted Mr. Bush's push for the bunker-buster for the past two years. Mr. Hobson chairs a House subcommittee that appropriates money for the nuclear weapons complex. He persuaded the House not to spend a cent for research on the bunker-buster. The Senate followed.

What worries him most about this weapon, Mr. Hobson has said, "is that some idiot might try to use it."

Defense Secretary Donald H. Rumsfeld told a Senate subcommittee in April that 70 countries are pursuing "activities underground."

"We don't have a capability of dealing with that," he testified. "We can't go in and get at things in solid rock underground." Mr. Rumsfeld suggested he needs the relatively small bunker-buster to avoid using "a large, dirty nuclear weapon."

Yet at the time of his testimony, Mr. Rumsfeld probably saw a study from the National Academy of Sciences estimating that the small bunker-buster, if used in an urban area, could cause more than a million deaths.

Pursuit of the bunker-buster and Mr. Rumsfeld's testimony confirm the administration's shift away from nuclear deterrence toward possible use of nuclear weapons in war. Under Mr. Bush's doctrine of pre-emption, the U.S. Strategic Command (STRATCOM) has added missions to its war plans. STRATCOM's global strike plan foresees the use of nuclear weapons to pre-empt an imminent threat from weapons of mass destruction or to destroy an adversary's WMD stockpiles.

The Pentagon's draft "Doctrine for Joint Nuclear Operations" describes these new missions. The draft was discovered on the Pentagon Web site in September by Hans Kristensen, now with the Federation of American Scientists. When Mr. Kristensen shared his find with the media, the draft disappeared from the Web site. But STRATCOM's war plans remain in force.

"You may win this year," Mr. Rumsfeld told Mr. Hobson in 2005, "but we'll be back." Meanwhile, Congress has mandated that any future earth-penetrator weapon must be based on conventional explosives.

The Pentagon had hedged its bets. In 2004, the Defense Department awarded a contract to Boeing to design and test a huge conventional bomb, to be known as the Massive Ordnance Penetrator. It would be the biggest conventional bomb in the U.S. arsenal, capable of demolishing "multistory buildings with hardened bunkers and tunnel facilities."

So why has the administration been pressing for a nuclear version?

The United States still has a massive Cold War arsenal. About 5,000 hydrogen bombs and warheads are deployed on intercontinental ballistic missiles, submarines and bombers; another 5,000 are held in reserve. In addition, 600 to 700 tactical nuclear weapons are ready for battlefield use.

Russia has fewer than 5,000 H-bombs deployed but many thousands more in reserve, and 3,000 tactical nuclear weapons. Many Russian nuclear weapons are not fully secured. Britain, France, China and Israel have several hundred nuclear weapons each. India and Pakistan are slowly building their arsenals.

In addition to the bunker-buster, the Bush administration wants new nuclear warheads to replace old ones. Daryl G. Kimball, executive director of the Arms Control Association, is dubious. He thinks the replacement process could be a back door to new warhead concepts, not what's needed when trying to persuade Iran to keep out of the nuclear club. A more meaningful approach, says Mr. Kimball, would be to slash the swollen U.S. and Russian arsenals.

Yet under the Treaty of Moscow, by 2012, both nuclear behemoths could still deploy 2,200 long-range nuclear weapons, not counting those in reserve and tactical arms. The world will still bristle with the most destructive of weapons of mass destruction 22 years after the Cold War's end.

That's not a prospect likely to dissuade the insecure leaders of Iran.