Race issue permeates Los Angeles mayor contest.(Knight Ridder Newspapers)

LOS ANGELES _ As the spirited mayoral contest in America's second-largest city enters its final days, the subject that has repeatedly vexed Los Angeles _ race _ has emerged again with the formation of political alliances seldom seen here.

Supporters of Antonio Villaraigosa, the former Assembly speaker, had hoped that a multiethnic coalition would make him the first Latino to win the mayor's office in more than a century.

But in the last week of the campaign, his opponent, James K. Hahn, who is white, has come from behind by building an unlikely coalition of centrist to conservative whites and liberal African-Americans.

The election takes place as Los Angeles leaves behind a decade of remarkable demographic change and social upheaval. Latinos are on the verge of becoming a majority in a city that for years defined its politics in black and white.

Race has always been an especially contentious subject in the city, which has endured the Watts riots, the police beating of Rodney King and the polarizing O.J. Simpson trial.

In this campaign, race is playing a subtler but nevertheless pervasive role as voters prepare to cast their ballots Tuesday. Both black voters and moderate to conservative whites have become key constituencies to the election and both candidates are trying to win them over.

Villaraigosa and Hahn, the Los Angeles city attorney, are both young Democrats with moderate-to-liberal positions on economic development and quality-of-life issues. So the campaign has been played out not along ideological lines but largely according to experience, personality and other intangibles.