On the day before a key U.N. inspectors' report, Secretary of State Colin Powell went before the world's political and economic elite in this mile-high Swiss resort Sunday to plead America's case for a possible war on Iraq.

"Multilateralism cannot become an excuse for inaction," Powell told the World Economic Forum, where the perceived unilateralism of the Bush administration has taken a beating this past week.

When U.N. chief weapons inspector Hans Blix presents his report today, "there will be no great rush to judgment today or tomorrow," Powell said, "but clearly time is running out. We must have Iraqi participation in disarmament, or it will be disarmed."

By all signs, Powell, a popular figure here, impressed everyone but probably won over few who didn't already back the American position. About half the audience rose to applaud when he came in; the others sat in stony silence. About the same proportion stood or sat when he ended.

The annual forum draws more than 2,000 corporate leaders and government officials from around the world. A large number have studied or worked in the United States, and, under normal circumstances, should be an easy sell.

Not this year.

The current forum, meeting under the slogan "Building Trust" in business, has turned instead into a weeklong debate on America's use of its overwhelming power in general and on Iraq in particular.

Powell came four days after Defense Secretary Donald Rumsfeld gibed that France and Germany, two of America's most reluctant allies, represent the "old Europe," which is in contrast with the "new Europe" farther east. The West Europeans were infuriated, and Rumsfeld's remark comes up in virtually every conversation in Davos on trans-Atlantic relations.

Powell's speech soothed hard feelings, but it did little to end the debate.

"Before you hang somebody, you deliver the evidence," a Dutch banker, Hubertus Heemskerk, executive chairman of Rabobank, told Powell. "If he doesn't cooperate with delivering the evidence, you don't do like you did in the Middle Ages. Yes, we are all very impatient [with Saddam Hussein] but we want to see the evidence. When we see the evidence, we Europeans will go to war with you."

"I think the evidence is there, and I think the evidence is clear," Powell responded. An Italian newspaper quoted him Monday as saying a "good part" that evidence could be made public "in the next week or soon after."

Those who already opposed the war were unconvinced.

"He's a decent guy, but I don't think he changed any minds," Gareth Evans, the former Australian foreign minister who heads the International Crisis Group in Brussels, said Sunday. "We don't need much evidence, just enough to know that he [Hussein] is lying. But there's not enough yet ... if you want international support."

Powell emphasized that it is not up to UN inspectors to find a "smoking gun," but "it is about Iraq disclosing the full extent of its activities ... its failure to provide inspectors with information" on its weapons of mass destruction.

Powell listed specific Iraqi weapons that he said were unaccounted for--stocks of anthrax, 30,000 munitions capable of delivering chemical weapons, mobile vans that have been used as chemical laboratories.

America's allies have pleaded for more time to let the inspectors finish their work, but Powell said that "it's not a matter of time. It's a matter of telling the truth." More time, he said, only gives Hussein more time to make links with al-Qaida -- Powell's only attempt to tie Iraq directly into the war on terrorism.

Two weeks ago, Powell sounded a different note on timing.

"The inspectors are really now starting to gain momentum," he said then, adding that their report due today would not be the last word but only "the first formal, official report."

Jordan's King Abdullah II also spoke at Davos on Sunday, and like Powell said that time was running out.