There is a kind of New Orleans gait: loose, ambling and deceptively laid back. It has to do with the heat, or maybe the cracked sidewalks, or the pretty buildings.

Don't let it fool you. Ray Nagin, the new mayor here, walks that shambling New Orleans walk, but by now, nobody mistakes it for relaxation. Six months into his term, Nagin has assaulted the most entrenched traditions of corruption in this city's Byzantine and musty politics. And he has done it with all the smiling guilelessness of a float rider at noon on Mardi Gras Day.

Those traditions say a new mayor's friends are richly rewarded, that little bribes grease small services and big bribes big services. They say that city taxes can be ignored and lucrative, if not quite straight-up businesses, can thrive, if one knows the right people.

Nearly every week, it seems, Nagin does something that puts him outside these old customs, as much as his shiny bald pate and long, gangling figure make him stand out in a crowd.

An obscure cable company executive from a modest background, Nagin came out of nowhere. His surprise victory in March resulted in part from voters' weariness of scandals. He had run his campaign arguing that the rotten political system was squashing economic development in his impoverished hometown, and he meant to change it.

Four months later, lunch counters downtown were abuzz: The new mayor had announced a crackdown on municipal corruption, and 84 people, including his nephew and the head of the city utilities department, were arrested. A top official in the tax-collection department abruptly quit amid evidence that favored businesses weren't paying taxes. New overseers of the city's decrepit public transportation system, who had come into power under the outgoing mayor with self-awarded six-figure salaries, were forced to resign. A lucrative patronage goodie that paid political heavyweights millions to send out dunning letters for property taxes was torpedoed. The former chief engineer in the city's property management department has been convicted of extorting kickbacks. A top school official is being investigated over fishy contracts.

The citizens' presumption here is always guilty until proven otherwise, and expectations are rarely disappointed.

But this hard-edged realism shows signs of wilting under the new regime, which has provoked as much curiosity as optimism. "I'm intrigued by the way he's approaching his job," said Jimmy Fitzmorris, a political veteran who began his career in the early 1950s as a city councilman under the last reform mayor, deLesseps S. "Chep" Morrison. (Later he was President John F. Kennedy's ambassador to the Organization of American States.) "The man reeks with sincerity."

In a state where five of eight officials elected to statewide office in 1991 have been convicted of criminal offenses, a sixth was the subject of a federal investigation and three are serving time (including former governor Edwin Edwards), this is new, and a little mysterious.

The mystery is compounded by Nagin. He's a black man elected by white voters; an instant politician with no ties to the local alphabet-soup of ward-heeling organizations, BOLD, SOUL and COUP, in a city with a 200-year tradition of political machinations; a novice who beat Richard Pennington -- the New Orleans police chief and former D.C. assistant police chief who was the anointed choice of the city's premier political boss, Rep. William J. Jefferson (D). Nagin is an unpolished speaker who uses words like "weird" in speeches and shuns many encounters with the media -- he declined to be interviewed for this story.

"This is the first non-traditional mayor we've had," said Silas Lee, a sociologist at Xavier University who has done polling for Nagin. "He's approaching it from the perspective of corporate America. And this is distinctive."

There have been false steps. Most of those arrested in July were merely cab drivers accused of paying bribes for their permits. Authorities allowed these black men and Asian immigrants to be photographed chained together. "A really humiliating display; it looked very disturbing," said Mary Howell, a New Orleans civil rights attorney.

In October, District Attorney Harry Connick (father of the crooner), an ally of Nagin's embattled predecessor, Marc Morial, threw out 53 of the cases, citing a lack of evidence. The utilities director was arrested in front of television cameras in a move Nagin's supporters and critics said was overkill. Critics howled even louder when the official's case was dismissed by a state court judge.

In spite of Connick's reluctance to proceed, the U.S. attorney's office is continuing the corruption investigations. And Nagin has insisted he will not back off.

Still, some prominent members of the city's political class believe that Nagin went off half-cocked and embarked on his highly public anti-corruption mission without developing the necessary evidence. Police have wanted to question Morial, who has refused to be interviewed, though he said he would submit to written questions.

"I think Mayor Nagin is well intentioned, but I think he got sold a bill of goods," said Patrick Fanning, Morial's attorney. He added that Nagin's advisers are pushing the anti-corruption crusade too far.

Dismayed black voices have also been raised against the mayor's "witch hunt," as the New Orleans Tribune, a black-oriented newspaper, put it in August. Nagin, the paper suggested, was merely a tool of those who have the "specific intent of dismantling and disparaging 24 years of black political control in New Orleans."

Still, the unexpected anti-corruption whirlwind appears to have left the man in the street bewildered, but enthusiastic. "We're staying put, waiting to feel where he's going at," said Darryl Press, a young welder taking a lunchtime break in the park across from city hall last week. "Everybody in my neighborhood is pretty happy with him," Press said. "They like the cleaning up.Yes, indeed. That's why people don't want to come down to the city, 'cause of all that underhanded stuff."

Others are merely stunned by the newness of it, certain that the computer-savvy technocrat in city hall is bringing change but unsure exactly what it means. "His unbelievable knowledge of the Internet," said Jules Edwards, an elderly shoe repairman on Magazine Street, struggling to put his finger on how the new mayor is different. "Nagin is the best thing that's happened to this city in my lifetime," Edwards concluded.

The white neighborhoods uptown, the corporate suites downtown and the Times-Picayune (its endorsement pushed Nagin out of single digits) are cheering too. But sociologist Lee said the new mayor's ratings are nearly as high among blacks as whites. He entered office with support that was more broad-based racially than perhaps any mayor in the city's history. He won all the majority-white precincts, and nearly half the majority-black ones, as well. And he did particularly well in upper-income black neighborhoods.

Still, he was born at Charity Hospital, son of a 7th Ward fabric cutter and the manager of a Kmart lunch counter. And the looseness of his syntax is a reminder that, for all the big money he earned as the local head of Cox Communications, his roots are in the city's working-class neighborhoods.

When Nagin was growing up and going to parochial schools, these neighborhoods were full of old shotgun houses and what New Orleanians call "doubles," double-sided wood-frame dwellings -- all very modest, but solid. Today, large swathes of these districts are crumbling, visible symbols of the city's decline and its 28 percent poverty rate.

"We may be renovating," Nagin told the Tribune in September. "And when you renovate, you've got to tear a few things out so that you can reposition the house to be much better than it was."

New Orleans Mayor Ray Nagin, center, has assaulted the most entrenched traditions of the city's corrupt politics.