The debate about whether to confront Iraq has hinged to a large extent on how war against Iraq would affect the war on terror. The arguments on both sides, however, show little understanding of a world in which terrorists, not countries, represent the greatest security threat we face. Both sides have focused so heavily on the actions of governments that they have seriously underestimated the boon such a war would hand the radical Islamists of al Qaeda.

The administration has hung too much weight on the likelihood that "Iraq could decide on any given day to provide a biological or chemical weapon to a terrorist group," as President Bush argued in Cincinnati. Saddam Hussein has possessed these weapons since well before the Persian Gulf War and never made that decision in the past, knowing it would be a fatal mistake. (As the CIA has conceded, the Iraqi leader is most likely to make common cause with al Qaeda if his regime is imminently threatened.) The chance that Baghdad will soon acquire a nuclear weapon is a much better argument for invasion, but the White House has preferred to harp on fears of an unlikely alliance between the secularist Hussein and radical Islamists than to delve into geopolitics.

The most often cited objection in the debate has been that fighting Iraq would undermine the cooperation of other countries in the war against terror. That judgment is off as well: Public expressions of support might diminish, but most moderate Islamic regimes fear al Qaeda at least as much as we do and have been eager to work together, albeit quietly, on intelligence and law enforcement matters.

Yet the greatest terrorist dangers will likely come not from Hussein's cooperation with al Qaeda before the United States topples him but from the fact that his removal would present jihadists with rich new opportunities. Even if Iraqis greet GIs as liberators -- and some would -- the lesson of the past decade is that important parts of the Islamic world will not see it that way. When the United States freed Kuwait and protected Saudi Arabia in the Gulf War, it stoked the radicals' belief that Washington was seeking to dominate the Arab world and destroy Islam. For al Qaeda, this was a catalytic event.

The deployment to Somalia, surely one of the most selfless American military engagements ever, was perceived as a further step in this campaign. It prompted al Qaeda to dispatch operatives who later said they trained the forces that shot down American Black Hawk helicopters. When the United States and NATO acted to protect Bosnian and Kosovar Muslims, the extremists made much headway with their contentions that America was actually the string-puller behind Serb forces, which could easily have been restrained much earlier.

Now, thousands of recruits later, al Qaeda and its affiliates would find American forces in a post-Hussein Iraq to be an irresistible target. Administration officials have been airing a plan for an occupation modeled on Gen. Douglas MacArthur's regency in postwar Japan, which, they contend, will plant liberal democracy in the Arab world. In the extraordinarily unlikely case that Iraq -- a country with deep divisions and nothing like the support for its leadership or wartime experience that Japan had -- is pacified, the country will still be a magnet for jihadists from all over the world. Those who today blow up French tankers off Yemen or bars in Bali will soon be picking off GIs in Basra. For the 100,000 troops trying to maintain order in a country the size of California, this will be life at "Threatcon Delta," with weapons perpetually loaded and locked.

Even more worrisome, a war to remove weapons of mass destruction from Hussein's hands could result in their falling into more lethal ones. Iraq's chemical and biological weapons are distributed around the country, in hundreds of military stockpiles and dual-use factories. As Kenneth M. Pollack points out in "The Threatening Storm," "Baghdad now has a number of mobile [biological weapons] labs that can move around the country as needed, leaving no trace and having virtually no signature that Western intelligence can detect." Iraq has hundreds of tons of chemical weapons and precursors and thousands of liters of biological agents. Throughout the 1990s, the United States was repeatedly surprised by discoveries in the course of inspections and defectors' accounts of the extent of these programs. On any given day, we could locate only a fraction of these weapons.

In the fog of war, much of this material would rapidly be "privatized" -- liberated by colonels, security service operatives and soon-to-be unemployed scientists. They know there is a market for unconventional weapons, and they will have no trouble finding buyers. The U.S. military has never faced a mission like collecting all these weapons. Even with U.S. special forces combing the country, the collapse of the Iraqi regime could prove to be the greatest proliferation disaster in history. The beneficiaries will be terrorists who have no interest in the weapons for their deterrent value; they will just want to use them.

Are these reasons not to confront Iraq? Possibly not -- it depends on how great and how imminent one thinks the threat of a nuclear Iraq is. But they do argue for slowing the locomotive and thinking anew about the hierarchy of dangers before us.

The writer is a senior fellow at the Center for Strategic and International Studies and co-author of "The Age of Sacred Terror."