Unilateral US action against Iraq might make the international community less willing to help out with other American geopolitical priorities - such as the overall war against terrorism.
That is the blunt warning France, Germany, and other US allies are delivering to American diplomats as the UN Security Council debate over Iraq heats up this week.
And the US badly needs the help of other nations as it pursues Al Qaeda remnants around the globe. Defeating Saddam Hussein's massed armies in combat is one thing. Cracking terrorist cells whose funds and people move freely across frontiers is another.
"If we thumb our nose at others, they will be less willing to cooperate ... and if you're looking at the war on terror, we can't do it alone," says Joseph Nye, dean of Harvard University's John F. Kennedy School of Government.
This dilemma reflects the temptations the United States faces as the world's sole superpower, says Mr. Nye.
The nation's overwhelming military and economic might convinces its leaders that they can accomplish important goals without allies, if need be.
But while that may be true for some issues, it is not true for all. And if the US acts as if it does not need friends, it won't have any.
"That's the paradox of American power," says Nye. "We're the sole power, but not to the point we can do [everything] alone."
The surprisingly stiff allied resistance to what it sees as America's rush to war on Iraq has arisen in advance of next week's crucial progress report by UN weapons inspectors.
France, in particular, is attempting to make the report's Jan. 27 delivery just one more step in a long process - as opposed to a last obstacle before military action begins.
At the UN on Monday, French Foreign Minister Dominique de Villepin said that France would not yet approve the use of force to oust Saddam Hussein, and warned that the way the US and the UN handle the Iraq crisis will have bearing on what happens with crises in North Korea, the Middle East, and elsewhere.
The Iraqi crisis is thus a "benchmark," said Villepin.
German officials, among others, echoed the French objections.
German Foreign Minister Joschka Fischer warned that war with Iraq "would involve considerable and unpredictable risks for the global fight against terrorism."
US officials seemed to be caught a bit off guard by this resistance within the Security Council inner circle. On Tuesday, White House spokesman Ari Fleischer cast the dispute not as war versus peace but as action versus avoidance.
The Security Council should not "slide back into the deadend road that the 1990s represented in terms of allowing Saddam Hussein to continue to build up his weapons while the world looked the other way," said Mr. Fleischer.
President Bush himself was even tougher. In something of a prejudgment of whatever evidence weapons inspectors will present next week, Mr. Bush told reporters that "it is clear to me now" that Mr. Hussein is not complying with UN resolutions calling for his disarmament.
Asked how long he would wait before ordering military action, Bush said "I will let you know when the moment has come."
Seldom in recent diplomatic history have the words of nations that are nominal allies on such a crucial issue been so at odds.
The US, and to a certain extent Britain, on one side, and the Europeans on the other, convey completely different senses of urgency when it comes to the future of Iraq and Hussein.
For France and others, the inspections are an end in themselves. Whether they find anything or not, Hussein can make little progress toward acquiring weapons of mass destruction while the intrusive inspections are taking place, the thinking goes.
The inspections are certainly cheaper than war, in both financial and human terms. Why not simply let them continue?
That is an attitude that certainly seems to be reflected within the inspection teams themselves.
"We need quite a few months before we complete our job, and that is what I'm going to report to the Security Council next week," said Mohamed ElBaradei, head of the International Atomic Energy Agency and a member of the Iraq team.
The view of the United States is that the inspections are largely irrelevant, in terms of lessening the risks Hussein poses to America and to the world community. Consequently, their continuation would not represent progress so much as simply delay a day of reckoning.