Few of the people gathered in the San Francisco church knew quite what to expect from Kamala Harris.

It was 2003, and the two men she faced in her first political campaign were well-known brawlers locked in a rematch to become the city’s district attorney — one of whom was her former boss.

Ms. Harris was a little-known government lawyer who had landed in the local gossip pages for dating Willie Brown, one of the state’s most powerful politicians. The attack on her was obvious: political patronage, packaged with a whiff of sexual intrigue.

After an audience member asked about her ties to Mr. Brown, she rose from her seat at the front of the sanctuary as her two opponents, Bill Fazio and Terence Hallinan, looked on.

Ms. Harris walked behind Mr. Fazio, asking if the audience remembered how Mr. Hallinan had attacked him for being caught in a massage parlor in a 1998 raid. She walked behind Mr. Hallinan, asking if the audience remembered how Mr. Fazio had attacked him for being a “deadbeat dad” who failed to pay child support.