The Prime Minister delivers his speech Thursday at a dinner hosted by the Chicago Council on Foreign Relations.

Chicago — Much of the world doubts America's motives as it barrels towards war with Iraq — a war that could lead to Washington fatally undermining the United Nations, Jean Chrétien said Thursday in a speech to foreign policy experts.

"The price of being the world's only superpower is that its motives are sometimes questioned by others," the Prime Minister said.

"Great strength is not always perceived by others as benign. Not everyone around the world is prepared to take the word of the United States on faith."

It marked the first time Canada expressed suspicion of the Bush administration's motives for resorting to war to topple Iraqi President Saddam Hussein.

U.S. President George W. Bush insists Mr. Hussein has flouted UN calls to destroy his chemical, biological and nuclear weapons and research. Mr. Bush believes the desperate dictator has turned to Osama bin Laden's al-Qaeda in an alliance that directly threatens Americans.

Mr. Chrétien couched his skepticism in praise for U.S. leadership in facing down the danger posed by Mr. Hussein. But his criticism of Mr. Bush's eagerness to bring down the Iraqi regime regardless of the opinion of the United Nations was unusually explicit.

Mr. Chrétien has always left enough doubt as to where Canada stood on the use of force to disarm Iraq that he confounded, if not confused, his critics and bought time with an administration in Washington that is desperately looking for allies.

But there was no mistaking his message to the Council on Foreign Relations, a respected foreign policy think-tank.

He went so far as to suggest that it is the United States, rather than Iraq or even France or Germany, that will determine what kind of future the United Nations will have or whether it will have any future at all.

Mr. Bush has said repeatedly that UN failure to disarm Iraq after 12 years of Mr. Hussein's flouting its dictates will call the world body's viability into question.

On Thursday, Mr. Bush said the United Nations must help him confront Mr. Hussein or "fade into history as an ineffective, irrelevant, debating society."

Administration officials have taken to comparing the UN to the failed League of Nations, which collapsed after its feeble efforts to head off the Second World War.

Mr. Chrétien took a decidedly different view.

"The world learned a terrible lesson when the League of Nations failed to act against aggression in the 1930's," the Prime Minister said. "But we must also remember that the League of Nations was mortally wounded because the United States was not a member."

Mr. Chrétien's address was a spirited defence of multilateralism, or a rejection of the notion that the destinies of the planet should be decided only in the White House and the Pentagon.

But his defence of multilateralism comes as the UN is hopelessly riven by a dispute over how to deal with Iraq.

The United States and Britain insist Iraq has already shown itself to have broken the latest UN resolutions calling for its disarmament and want the world body to authorize military action.

Several other members of the UN Security Council, led by traditional U.S. allies France and Germany, have thwarted the Anglo-American call for war and threatened to veto any resolution that demands a strike against Baghdad.

Russia joined France and Germany in demanding strengthened weapons inspections in Iraq, which the Bush administration considers virtually useless.

"How the United States acts in the days ahead will have profound consequences for the future," Mr. Chrétien said. "I am convinced that working through the United Nations if at all possible, as difficult and as frustrating as it sometimes can be, will not only immediately strengthen the hand of the United States, but also those around the world who want to support it."

Mr. Chrétien said acting without international support could make any war with Iraq a war of East versus West, or the strong versus the weak.

"It is imperative to avoid the perception of a 'clash of civilizations.' Maximum use of the United Nations will minimize that risk."

Mr. Chrétien also rose to the defence of another beleaguered multilateral organization: NATO.

The alliance was thrown into one of its worst-ever crises Monday when France, Germany and Belgium vetoed a U.S. request for NATO to make plans to protect Turkey if Mr. Hussein Hussein attacks.