WASHINGTON, 25 May 2004 — President Bush is hearing increasingly bleak warnings that the US occupation of Iraq is heading for failure — from Republican and Democratic members of Congress, current and former officials, and even some military officers still on active duty.

But so far, at least, the White House says it hasn’t heard anything that makes it want to change course.

Weeks of military and political setbacks have produced a striking change of mood in the capital about the prospects of success in Iraq, where US and allied forces are struggling to establish security to allow a new Iraqi “caretaker government” to assume limited powers on June 30.

A series of Senate hearings last week showcased the growing fears of many foreign policy experts — a mood some described as “panic.” “I believe we are absolutely on the brink of failure,” retired Marine Gen. Joseph P. Hoar, a former commander of US forces in the Middle East, told the Senate Foreign Relations Committee. “We are looking into the abyss. We cannot start soon enough to begin the turnaround.”

“If the current situation persists, we will continue fighting one form of Iraqi insurgency after another — with too little legitimacy, too little will and too few resources,” warned Larry Diamond, a former adviser to the US occupation authority in Baghdad. “There is only one word for a situation in which you cannot win and you cannot withdraw: Quagmire.”

Hoar and Diamond’s assessments were grimmer than most. But the two men were far from alone.

Maj. Gen. Charles H. Swannack Jr., the current commander of the army’s 82d Airborne Division, which returned from Iraq in April, has given reporters an equally blunt assessment. “We are winning tactically, but have made a few tactical blunders . . . (which) created strategic consequences in world opinion,” Swannack said in an e-mail message. “We are losing public support regionally, internationally and within America — thus, currently, we are losing strategically.” He added: “I believe Operation Iraqi Freedom is a just cause, America needs to stay the course and we must regain the moral high ground.”

Another active-duty officer who recently returned from Iraq — and who spoke on condition he not be identified — was crisper. “We could not have screwed up more if we had set out to do it deliberately,” he said. “We gave ourselves all the disadvantages of occupation, but none of the advantages.”

Even Sen. Richard G. Lugar, R.-Ind., the cautious chairman of the Foreign Relations Committee, warned that the United States might be headed for a dead end unless the administration outlines a clearer strategy.

“A detailed plan is necessary to prove to our allies and to Iraqis that we have a strategy, and that we are committed to making it work,” Lugar told Bush administration officials at a hearing. “If we cannot provide this clarity, we risk the loss of support of the American people, loss of potential contributions from our allies and the disillusionment of Iraqis.”

Leslie H. Gelb, a former president of the private Council on Foreign Relations — and a top Pentagon strategist during the Vietnam War — said he has never seen confidence sink as quickly in Washington as during the past few weeks.

“I’ve never heard the kind of dark defeatism I’m hearing now, both in and out of government, including the worst days of the Vietnam War,” said Gelb, a Democrat. “Support for this war is plummeting. In Vietnam, that happened much more slowly, and only after much higher casualties.”

Not everyone agrees. Gen. Richard B. Myers, chairman of the Joint Chiefs of Staff, told a House committee on Friday that he thought Gen. Hoar and other critics were wrong. “It’s going to be tough, but no, I don’t think we’re on the brink of failure; I think we’re on the brink of success here,” Myers said. “I think that as the new transitional government stands up, that there will be traction there with the Iraqi people that will be very important to them. And I think we’ll continue to move forward.”

“Don’t panic,” counseled Phebe Marr, an Iraq expert at the National Defense University and former CIA official. “It is worse than I had thought it was going to be, worse than most people thought it was going to be. But no one is considering just leaving -— because the (result) would be not just that Iraq would go down the drain, but that it would be a center of terrorism.”

Still, Marr said that when she briefed midlevel State Department officials recently, the mood she encountered was: “Help! Help! We can fail here!”

To counter that spreading sense of disorder and shore up public support, President Bush plans to give six major speeches on Iraq in the six weeks remaining before the transfer of sovereignty to the new transitional government, White House officials said.

Officials said Bush plans to explain his strategy in Iraq in greater detail, and warn that there will probably be more setbacks — and more US casualties — ahead.

Officials said there was no immediate sign that Bush is planning to announce any major new initiatives or shifts in policy in his speech. The main theme, one aide said, will be a familiar one: “Stay the course.”

The White House wants to avoid a politically damaging letdown if the transfer of sovereignty on June 30 does not visibly improve the military situation.

Senior officials have long warned that the June 30 milestone could produce an upsurge in violence.

“I would predict . . . that the situation will become more violent even after sovereignty,” warned Gen. John Abizaid, the current commander of US forces in the Middle East. “So it’s possible that we might need more forces.” If Bush decides to make a serious change in strategy, there is no shortage of suggestions.

Some hawks, such as Sen. John S. McCain, R-Ariz., and Rep. John P. Murtha, D-Pa., have called for a significant increase in troop strength in Iraq. But Abizaid has said he doesn’t believe more troops would do the trick. Several foreign policy experts, including Diamond and Gelb, have proposed that the United States set a target date for withdrawing its troops to make it clear that the occupation won’t last forever. Bush aides dismiss that idea. “It would just encourage the bad guys to wait us out,” said one.