Mark Leno’s win in the Democratic primary race for the District 3 state Senate seat was largely due to the overwhelming support from his San Francisco base combined with his success in winning votes in the Marin area, an analyst and a consultant for one of Leno’s competitors both said a day after the election.

With 100 percent of the vote counted, Leno, an Assemblyman from San Francisco, had 43 percent. Trailing was Joe Nation, a former Assemblyman from Marion, with 29.3 percent, and incumbent Carole Migden, with 27.7 percent. With minimal Republican opposition in the fall, Leno is almost certain to win the seat.

Perhaps most striking about Leno’s win was 57.1 percent vote pickup in San Francisco.

Nation’s campaign had pinned their hopes on Migden, a longtime San Francisco public official, taking votes from Leno’s column in San Francisco, but it wasn’t to be. The embattled Migden, who in the last year has faced a rash of negative stories ranging from her driving to her campaign finance records, won just over 31 percent of the vote in the area.

“Mark really coalesced the San Francisco vote,” said Jim Ross, an adviser to Nation. “Carole didn’t split up enough of the San Francisco vote.”

“Leno just won overwhelmingly in San Francisco, so that was the race,” said David Latterman, a San Francisco-based analyst. “San Francisco won it for Leno.”

Nation faced an uphill climb in holding Leno’s San Francisco onslaught to a minimum, said Latterman. Aside from Migden’s inability to regain control of her public image and dig into her support in the city, Nation was running as a moderate in a liberal area. “Nation politically was to the right of where people here are,” argued Latterman.

Leno benefitted, meanwhile, from a well-timed Saturday endorsement from House Speaker Nancy Pelosi, arriving in time for the Sunday newspapers and newscasts.

Leno’s victory was also aided by a strong showing in Marin, Nation’s home base. Election returns show Leno winning 34.8 percent, with Nation at 43 percent and Migden at 22.2 percent. Nation aides believed they needed more than an 8 percent margin in the area. They also say they needed a turnout larger than the 35,000 who cast ballots.