Los Angeles has elected its first Latino mayor in more than a century: Antonio Villaraigosa defeated incumbent Jim Hahn in a landslide, 59 to 41 percent. As mayor of the country’s second-biggest city, Villaraigosa immediately becomes a national political figure in the Democratic Party. But he’s not just a Latino; he’s also a longtime labor activist who started out as a union organizer and then headed the ACLU of Southern California.

This was Villaraigosa’s second try–he was defeated four years ago when Hahn ran a vicious campaign that successfully exploited black fears about electing a Latino mayor. Hahn lost his African-American support when he fired the black police chief, Bernard Parks, who then ran against him in this year’s primary. Villaraigosa knows his key political task is cementing a progressive alliance between Latinos and blacks. If he can do that, he will point the way to a new liberal-left coalition and make political history not just for LA but for the country.

Latino candidates nationwide have followed sharply different political trajectories, and California has exemplified this fact: Until today, the highest-ranking Latino elected official in LA history was the current city attorney, Rocky Delgadillo, elected four years ago with the support of businessmen and real estate developers. Villaraigosa’s labor background provides a clear political alternative for the 4 million Latinos who live in LA County.

Villaraigosa’s election is part of a historic transformation of Los Angeles, which fifty years ago was the whitest big city in the country as well as the most anti-union. During the 1960s white liberals on the West Side allied with blacks, leading to the 1973 election of Tom Bradley as the city’s first black mayor. Then, white-backlash politics brought Republicans to City Hall (and the governor’s mansion in Sacramento). But starting in the 1990s LA became a dynamic union city, mostly because progressive unions mobilized an immigrant workforce that was heavily Latino. Two unions have been key: the janitors local of the Service Employees union (SEIU), and the hotel workers local of the Hotel Employees and Restaurant Employees (which merged last year with UNITE to form UNITE HERE). The result, in the words of Harold Meyerson, op-ed columnist for the Washington Post and political editor of the LA Weekly, is “the most astonishing and significant civic transformation in recent American history”–and Villaraigosa’s election is their greatest achievement.

The wrinkle in this election came when organized labor–the LA County Federation of Labor, 350 unions strong–endorsed the incumbent Hahn rather than Villaraigosa. They reasoned that Hahn had delivered on his promises to labor, supporting hotel workers and home healthcare workers and opposing Wal-Mart; but as Marc Cooper has argued, this “expedient alliance” is a black mark on labor’s political record. For the second time Hahn ran a classic smear campaign, featuring TV ads that portrayed Villaraigosa as soft on crime, pro-gang, anti-police and anti-religious–and this was the campaign that organized labor supported. But the rank and file seems to have ignored the endorsement, bringing to an end this unfortunate chapter.

As mayor, Villaraigosa will now have to find money for two big promises he made–to expand the city’s subway system and to increase funding for the suffering public schools. He can’t do this without help from Washington and Sacramento, but he’s obviously unlikely to find much in either city. The feeling in LA is that Antonio could do great things for the Democrats on the national scene–but first he has to succeed at the challenges he set himself in LA.