Most days, he jogs around the once splendid gardens of Saddam Hussein's Republican Palace, behind which his trailer is perched, and is at his desk inside the marbled halls an hour later wearing a suit and Army-issue combat boots.

When he moves out beyond the palace walls, now girded by an endless helix of razor wire, he has around-the-clock protection from a force of former Navy Seals and Army guards. Most Iraqis know very little about him except that he is whisked through their streets sandwiched between machine gunners in a convoy and that he appears on television with a fresh kerchief in his pocket and those size 10 1/2 desert boots, which he even wore to the World Economic Forum in Jordan last month. ("I thought he had forgotten to change," a Western colleague commented.) 

In the dust of Iraq, the boots, Mr. Bremer says, are an attempt to spare his dress shoes. But they also signify that he is engaged in managerial combat.

For Mr. Bremer, the 61-year-old occupation administrator of Iraq, the daunting problems of the most complex and expensive nation-building tasks the United States has undertaken in a half-century have only intensified since President Bush appointed him on May 6.

The economy remains devastated and moribund. Electricity supplies to the capital are failing. Guerrilla attacks on American troops are increasing. Mr. Hussein has returned as a disembodied voice on audiotape exhorting his followers to rebellion and sabotage.

Mr. Bremer's notion that he could run Iraq on the strength of decisive and firm management policies has given way, a number of Western and Iraqi officials say, to the realization that he desperately needs an Iraqi governing body to share responsibility — or blame — for the long-term task of establishing postwar order and stability.

"There has been a process of coming down to earth," said Hoshyar Zebari, the affable policy aide to the Kurdish leader Massoud Barzani.

When Mr. Bremer arrived in Baghdad on May 12, he inherited a landscape of collapsed government, burned-out ministries, looted universities and commercial centers and police and security forces that had fled or abandoned their posts.

The devastation had overwhelmed the first wave of diplomats, civilian aid workers and military personnel working under Jay M. Garner, a retired lieutenant general. General Garner was the reconstruction administrator selected by Gen. Tommy R. Franks, the overall commander of allied forces during the war.

"They told us to bring two suits," said one of General Garner's former aides. "We thought we would be walking into functioning ministries, that we would fire the Baathists in the top jobs, and get the trains running again in a couple of months." It was not to be. 

But when Mr. Bremer arrived with a personal mandate from Mr. Bush and an "I'm-in-charge" message, he conveyed a sense that the mayhem would soon be over. On his desk in the elegant wood-paneled study he appropriated from the Iraqi dictator, Mr. Bremer planted a hand-carved motto: "Success has a thousand fathers," an admonition for teamwork and an implicit rejection of the second line of the aphorism that failure is an orphan. 

"There won't be any failure," he said.

In selecting Mr. Bremer for the job of winning the peace in a country that has known only iron-fisted totalitarian rule for a quarter-century, Mr. Bush settled on the candidate who appears, up to now, to have straddled the ideological divide between the State Department and Pentagon over the kind of crisis management needed to protect the allied victory here.

To Pentagon conservatives, Mr. Bremer has strong credentials as the tough counterterrorism chief in the Reagan administration and as a longtime protégé of Henry A. Kissinger, the former secretary of state. With Mr. Bremer's 23-year career as a diplomat, his conservatism is leavened with a strong pragmatic instinct. 

"As forceful as he is, he certainly is not dogmatic," said Sérgio Vieira de Mello, the United Nations special representative in Baghdad.