ALMOST THREE YEARS AGO, the United States invaded Iraq, based on bogus, unconfirmed, cherry-picked intelligence that Iraq had chemical and biological weapons and an active nuclear program. The invasion was preceded by massive worldwide opposition. There was no shortage of knowledgeable dissenting voices telling the Bush administration that Iraq did not have weapons of mass destruction; that Saddam Hussein's ambitions to obtain such weapons had been successfully checked through sanctions and international inspections and could continue to be; that the United States was about to make a mistake of historic proportions -- one that could conceivably lead to World War III.

None of this fazed George W. Bush at all. He ignored everyone outside his tiny circle and invaded. It soon became clear that the critics had been right: There were no weapons of mass destruction. And the insurgency triggered by the Bush administration's stunningly inept series of postwar decisions and actions has done the seemingly impossible: made Iraq more of a hell on earth to live in than it was under Hussein. It has also destabilized the entire region, and made the world a much more dangerous place.

Why am I saying all this? Because of Iran. While Bush was invading a country that posed no threat to U.S. national security, and turning it into a cauldron of terrorism, next-door neighbor Iran was building up its own nuclear program -- and in such a way that it would be next to impossible for the U.S. to take out.

"I believe the West has played this game too late and played into Iranian hands," said Abbas Milani, director of Iranian studies at Stanford University. "At this stage, they are convinced that the more hardball they play, the more the West will collapse." Mr. Milani said that news reports from Iran suggested that its government had used the last few years to sign up oil deals with various countries to gain their political support, dispersed its nuclear activities to some 300 sites around the country and stockpiled food, medicine and other materials to survive any sanctions.

The Iraq war has used up American military and political clout that is now no longer available to deal with the Iranian threat either diplomatically OR militarily. I think war is almost always the wrong choice, but assuming that war with Iran under these circumstances would be justifiable, the Bush administration has foreclosed that possibility. Airstrikes would not be viable with such a decentralized nuclear program; and in any case, as even the Bush administration knows, any direct military action against Iraq would result in immediate retaliation against Americans in Iraq.

Which makes one wonder: Whatever happened to the "intimidation value" of the United States invading Iraq?

A few years ago, for example, Bush administration hawks spoke of the powerfully persuasive effect on Iran of 150,000 American troops in neighboring Iraq. Now, the United States is angrily calling on Iran not to support lethal attacks on American troops by insurgents. There remain some in the Bush administration who say that American officials could have made a greater attempt in the last year or so to reach out to the Tehran government. But there is no indication that Iran was interested.

Another neoconservative assumption that turned out to be so much garbage.