But that's right where this page is. More discussion is the only road that will get the world to the right outcome — concerted effort by a wide coalition of nations to force Saddam Hussein to give up his weapons of mass destruction. We need another debate. Another struggle to make this the United Nations' leadership moment.

Right now, things don't look promising for those of us who believe this is a war worth waging, but only with broad international support. The United States has an invasion force in place, and the military's schedule seems to demand that it attack within a few weeks before spring brings on withering desert heat. Washington has some support among other nations, but many of them are newcomers to the world of high-stakes diplomacy and few have much to offer in the way of troops or financial support. Prime Minister Tony Blair of Britain, America's only strong and consistent ally among the world's other major military powers, is facing fierce opposition at home and ridicule abroad for his allegiance to the Bush administration. Turkey, another important ally, held out for more money as it considered whether to allow American invasion forces on its soil. The size of the Turkish demands made the anti-Iraq forces look less like a serious coalition than a diplomatic version of "Let's Make a Deal."

Saddam Hussein, meanwhile, has been skillful at providing the pretense of progress to international inspectors without seriously cooperating. Iraq has drawn the United Nations into a game of find the handkerchief, in which the burden is on the inspectors to track down mobile laboratories or sniff out hidden weapons. All this puts an enormous weight on what Iraqi behavior Hans Blix, the chief U.N. inspector, chooses to stress — whether he dwells on Iraqi resistance or points to areas of cooperation. In the United Nations, the equivalent of a C-minus for effort on a Blix report can be taken as an argument for peace, while a D-plus can be seen as a call to war. The inspectors should never be put in the position of deciding international foreign policy.

A Case for Action

While the possibility of Mr. Hussein experiencing a last-minute conversion seems minuscule, there is one quick way to test whether it's possible. Iraq has Al Samoud 2 missiles, weapons it built at great expense and effort. Mr. Blix has already stated that they are too powerful, able to travel too far to fit under the limits the United Nations placed on Iraq after the Persian Gulf war. On Friday, Mr. Blix told the Iraqis to destroy them.

This week the United Nations should tell Mr. Hussein he must let the inspectors watch him get rid of his missiles immediately, or outside forces will do it for him, with the support of the international community. That clear message would resolve the most frustrating problem for those who want the United Nations to nail down its position as the arbiter of world crises — how to get France and its supporters to define their own bottom line rather than simply criticizing Washington's.

Saddam Hussein is nobody's hero in this story. Although many Americans are puzzled about why the Bush administration chose to pick this fight now, it's not surprising that in the wake of Sept. 11, the president would want to make the world safer, and that one of his top priorities would be eliminating Iraq's ability to create biological, chemical and nuclear weapons. Of all the military powers in the world, Iraq is the one that has twice invaded its neighbors without provocation and that has used chemical weapons both on its military foes and some of its own restive people. North Korea may be a greater danger, but North Korea has not been told by the United Nations to disarm and stay disarmed. And, although the administration is careful to steer clear of this argument, the very fact that North Korea has the international community in a bind is a cautionary tale for making sure that no other despotic governments run by irrational adventurers get hold of nuclear arms.

A Game of Chance

It seems clear to us that the United Nations should enforce its own orders and make Iraq disarm, even if that requires force. But in the end, sometime in March, the United States may have to decide whether it should do the job on its own.

When that happens, the arguments on both sides are sure to be couched in the highest moral principles. But the real calculations will be entirely about the odds of succeeding. If military victory over Iraq is swift, and if it can be accomplished without extensive casualties to American soldiers or Iraqi civilians or damage to neighboring countries or the area's oil fields, Mr. Bush's popularity will soar. If occupation forces unearth proof of a large nuclear program, stockpiles of terrifying biological weapons and real evidence of serious collusion between Saddam Hussein and international terrorists, many of the international leaders who are riding the crest of anti-Americanism now will start looking very foolish.

But things could go terribly wrong, very quickly. The war could be brutal and protracted, especially if Mr. Hussein unleashes biological or chemical weapons against Israel or American troops. He may also succeed in setting fire to his oil wells, or disabling those in neighboring countries, crippling the world economy. And if he is destroyed, there is every possibility of a vicious struggle for the lucrative spoils among the disparate clans and ethnic groups in Iraq, drawing in Turkey, Iran and others. In the chaos, the weapons of mass destruction Americans went to war to eliminate could wind up being ferried out of Iraq and sold to the highest terrorist bidder. And just as the American military's presence in Saudi Arabia during the gulf war precipitated the growth of Al Qaeda and Sept. 11, the long-term occupation of Iraq will create resentment in the Muslim world that could lead to more, not less, terrorism.

The Long Haul

All those risks, we repeat, are worth taking in the context of a broad international coalition, and some might even be diminished if the world acts together. The country is still traumatized by the discovery on Sept. 11, 2001, that we live in a world of unimaginable danger. Some of our traditional allies knew that already, from long and terrible experience. Some are still trying to face up to it. But the rational response is to work together to make the world safer, not to ignore obvious dangers in hope that the likely will not become inevitable.

Our own guess, when we calculate the odds in Iraq, is that the war is likely to go well in the short run, but that the long run will be messy, difficult and dangerous. If America acts virtually on its own, it is hard to imagine either the Bush administration or the American people having the staying power to make things right. Washington may be counting on Iraq's oil revenue to pay for rebuilding the country after the war, but the oil wells could be damaged in the fighting. It seems certain that an administration that will not give up tax cuts to pay for the war itself is not going to inflict economic pain at home to pay for the cleanup. And while Americans have always shown themselves willing to risk anything, even their own children, for a critical cause of high purpose, their support for this particular fight is thin as a wafer and based on misapprehension that Iraq is clearly linked to terrorism.

Our Bottom Line

When all the odds are calculated, people will have their own particular critical concerns that add weight to one side of the scale or the other. For some, it is the belief that rogue nations can be deterred — a certainty that if they use their worst weapons, the United States and its allies will pay them back, double. While the evidence that Saddam Hussein has used chemical weapons in battle with Iran, and against his own Kurdish population, is strong, the fact that he has not used similar weapons in other situations, including the gulf war, suggests that deterrence should not be dismissed.

For others, the bottom line will come down to saving face. The United States has assembled its forces for invasion, and to back down now, many argue, will be to show a weakness that will encourage our enemies. We don't think the world's only surviving superpower should be making war to avoid embarrassment.

Our own overriding concern runs in the other direction. The United States is, and seems likely to remain, a nation whose military might and economic power so outstrip any other country that much of the world has begun comparing it to ancient Rome. The test now is whether we will find a new way to exercise our power in which leadership, self-discipline and concern for the common good will outweigh our smaller impulses. An invasion of Iraq that is not supported by many traditional allies, or those powers that we need to be allied with in the best possible future, will send a message that we can do whatever we want. But it is not going to make the rest of the world want to root for us to succeed. The real test of American leadership is only incidentally about Iraq. It is whether we will further split the world into squabbling camps, united only by their jealousy of our power, or use our influence to unite it around a shared vision of progress, human rights and mutual responsibility.