Dan Lungren’s victory in California’s 3rd district Republican primary this month was the first surprise of the early Congressional primary season.

It was also a rare draw between the conservative Club for Growth and the more centrist Republican Main Street Partnership. Both backed losing horses.

The Club for Growth sided with the runner-up in the Sacramento-area race, state Sen. Rico Oller (R), who finished 2 points behind Lungren. RMSP backed third-place finisher Mary Ose, sister of retiring Rep. Doug Ose, a leading Republican moderate.

RMSP was quick to endorse Lungren (a former five-term lawmaker seeking a return to the House) for his general election contest against Gabe Castillo (D), a little-known financial adviser. On March 3, one day after the primary, the group issued a news release congratulating the victor.

“The primary is over — it is time for all Republicans to work as a team,” RMSP President Sarah Chamberlain Resnick said, noting that Lungren worked well with his centrist Republican colleagues when he served in Congress from 1978 to 1988.

Of course, the GOP was in the minority back then, so the party couldn’t

afford the kind of internecine warfare that sometimes accompanies its ideological squabbles now that it controls both chambers.

The Club for Growth did not embrace Lungren so quickly — but then Oller did not concede until eight days after the primary, following a count of absentee ballots.

The club’s executive director, David Keating, said this week that his group can live with Lungren as well.

“The second-best candidate won the primary,” he said.

That both groups are accepting Lungren says something about the former California attorney general’s appeal — and the dynamics of the heated 3rd district primary race, which in the end became a classic example of a political murder-suicide.

Ose and Oller each spent upwards of $1 million on the primary — much of it used on negative ads against each other. Lungren spent roughly half that. Club for Growth and RMSP were also on the air with very tough ads about their opponents.

As one California Republican operative noted, “The guy that nobody wanted ended up winning because the two that everybody wanted ended up killing each other. Dan was everybody’s second choice, though.”

Not that Lungren didn’t bring some assets to the table. In a campaign against a political neophyte (Ose) and a man whose experience is limited to eight years in the Legislature (Oller), Lungren touted his contacts and résumé.

“In today’s world, a Representative has to be engaged on issues at every level,” Lungren said last week. “The people of our district know that what happens in Iraq could well have as great an affect on their families as the more mundane, yet important, issues of traffic and water policy.”

And in the post-Sept. 11, 2001, world, three decades of experience on the statewide and national stage brings a certain kind of gravitas — a lesson, perhaps, for other candidates this election cycle.

“Lungren really does know Dick Cheney,” the Sacramento-based GOP strategist said of the vice president, who served with Lungren in the House. “He’ll be effective.”

Other factors contributed to Lungren’s victory. He received a late endorsement from another influential ex-colleague, former Speaker Newt Gingrich (R-Ga.), which helped inoculate him from Oller’s criticism that he is not conservative enough.

And Tom Sullivan, a popular conservative talk radio host in the Sacramento area — who had considered running for the seat himself — also endorsed Lungren, and essentially turned over his program to the Lungren campaign on the two days leading up to the primary.

Public and private polls showed that Lungren went into the weekend before the primary in third place, with Oller leading and Ose moving fast, meaning the late Gingrich endorsement, the Sullivan largess and the fall-out from his opponents’ negative ads all played a role in his showing. Lungren called his “great” come-from-behind victory “exhilarating.”

No fool, Lungren sought to reach out to the 62 percent of GOP primary voters who did not vote for him — and urged them to think big.

“I ... want to congratulate those who supported my opponents in the primary for their hard work, and to invite all the district’s voters to join with me in a united Republican effort this fall as we work together to secure not only a victory here in the 3rd, but a California victory for President Bush.”