Los Angeles Mayor James Hahn and challenger Antonio Villaraigosa came out swinging in their first mayoral debate, each saying the other couldn’t be trusted to run Los Angeles.

The hour-long debate at California State University, Northridge originally focused on education, immigration and traffic, but the candidates wasted little time in attacking each other on the issue of trust.

Villaraigosa, a councilman and former Assembly Speaker, repeatedly called Hahn’s administration “the most investigated since Frank Shaw,” citing the city’s 1930s-era mayor, who was recalled from office amid charges of corruption. “You’ve never seen my name associated with any scandal,” Villaraigosa said.

Hahn fired back, saying Villaraigosa couldn’t be trusted because he broke his word that he would serve a full term as councilman. “The issue, Mr. Villaraigosa, is the public’s trust of you, that you will serve out your full term and not seek another office,” he said.

That prompted Villaraigosa to say that circumstances had changed, and as the Hahn administration progressed, constituents requested he run to fill a leadership vacuum. “We can’t afford four more years of corruption probes and stagnation,” he said.

The clashes over trust overshadowed discussion of other issues, including education, traffic and public safety, though both Hahn and Villaraigosa refused to promise that they would not raise taxes to pay for more police.

Villaraigosa, meanwhile, defended himself against charges of hypocrisy for his decision to send his children to Catholic school instead of to the Los Angeles Unified School District.

“I’m proud of the fact that my children are in Catholic school. I want them to understand the role that faith plays for our family,” Villaraigosa said. Hahn shot back: “You should put your money where your mouth is. My children go to our neighborhood school.”

On reducing traffic congestion, Hahn called for adding more lanes to the Hollywood and Ventura (101) freeways and for putting more resources into light rail. Villaraigosa repeated his call for extending the Red Line to the Pacific Ocean, saying he would vigorously lobby Washington and Sacramento for L.A.’s fair share of transit funds.

As he defended himself, Hahn also repeated allegations that Villaraigosa took money from Enron Corp., supported an energy deregulation scheme that went awry and made spending decisions as Speaker that ended up depriving tens of millions of dollars from Los Angeles.

“If anyone shows me that I allowed, encouraged or directed anybody to break the law, I will certainly hold myself accountable,” Hahn said. “But you need to hold yourself accountable for your decisions in Sacramento,” Hahn said to Villaraigosa.

The sparring continued during separate press conferences following the debate, with Villaraigosa pledging to serve out a full term as mayor if elected. Hahn, meanwhile, defended himself against a Villaraigosa charge that he was “missing in action” during a month-long Metropolitan Transportation Authority mechanics’ strike 18 months ago, saying he worked behind the scenes.