As a candidate for mayor, Antonio Villaraigosa (search) packaged his ethnicity as carefully as he knotted one of his designer ties. Looking to appeal across the racial rainbow, he became the candidate who happened to be Hispanic, not the Hispanic candidate.

But only days after his watershed election as the first Hispanic mayor of modern Los Angeles, fighting between black and Latino high school students forced him to speak to the racial lines that crisscross — and sometimes divide — one of the nation's most diverse cities.

On issues ranging from jobs to housing to education, the city's complex and shifting racial milieu will test his promise to be a mayor "for all Los Angeles."

Among blacks and Latinos, "at the street level, the tensions are there, at schools, over employment," said Harry Pachon, director of the Tomas Rivera Policy Institute at the University of Southern California.

Schoolyard fights are commonplace, but the racial rivalries that played a part in recent brawls at Jefferson High School gave the mayor-elect an early opportunity to take up the role of civic and cultural bridge-builder he talked about during his campaign.

A May 26 fight involving several dozen black and Hispanic teens at the school was so serious that school police used batons and pepper spray to break it up. It was the third racially motivated brawl in six weeks at the overwhelmingly Hispanic school.

Villaraigosa was at the school the next day, meeting with teachers and students. He is reviewing the organization of the mayor's office to determine if a special office for race and safety issues is needed to work with the Los Angeles Unified School District, which runs the 800-campus system.

"One of the most important responsibilities for the next mayor is to help bring this city together," said Villaraigosa, 52, the son of a Mexican immigrant. "We cannot allow — in a city as diverse as this one — racial violence in our schools. We've got to have a zero tolerance for it."

Villaraigosa's election as the city's first Latino mayor since 1872 was the latest sign of expanding Latino political clout in California and across the nation. He knit together Hispanics, blacks and left-leaning whites — a coalition that some analysts called a new paradigm in urban politics.

When he takes office July 1, Villaraigosa will inherit a city with chronic growing pains. Steady population growth has contributed to snarled traffic, housing shortages and a troubled school system. Downtown needs a makeover, the airport a major renovation.

And while he has elevated expectations for a new period of racial and ethnic cooperation, recent history shows volatile issues can quickly alter the political landscape.

Tensions flared in February after police shot and killed a black teenager who was driving a stolen car. Police treatment of a car-theft suspect who was hammered repeatedly with a steel flashlight after a chase in South Los Angeles last year recalled the infamous case of Rodney King (search), the black motorist beaten by white officers.

Mayor James Hahn's popularity among blacks plummeted after he helped push out the city's black police chief in 2002. The issue contributed to Hahn's loss to Villaraigosa last month.

A Los Angeles Times exit poll in the May 17 election found that Villaraigosa was seen by supporters as someone who understood the city's cultural complexity and can bring people together. Still, race relations ranked well below education, gangs and jobs as top issues.

"Soothing racial tension is something he cares about, but it's not an easy thing to accomplish," said Matthew Streb, a political scientist at Loyola Marymount University who studies politics and race.

"Appearances at high schools are great, but people are going to ask 'what more are we going to see?' The average person on the street, are they willing to overcome their prejudices?"

Villaraigosa isn't alone in wanting to city to be more assertive on racial issues at schools.

"We can't just keep responding to this like a fire department — responding when something happens," said Police Chief William Bratton. "We need to focus much more on what we need to do to prevent it in the future."