Previewing the electoral potency of the illegal immigration issue among Republicans in the 2006 midterms, California state Sen. John Campbell (R) finds himself in a 48th district special-election runoff this December against Minuteman Project co-founder Jim Gilchrist and three others.

Gilchrist, running under the American Independent Party banner, captured 14.4 percent of the vote in Tuesday’s open primary, possibly preventing Campbell — who finished first in the open primary with 46 percent — from garnering the 50 percent plus one he needed to win the election outright and avoid the Dec. 6 runoff.

“It’s a brand new election and I’m glad to know we’re on solid ground with John Campbell,” Gilchrist campaign manager Howie Morgan said in a telephone interview Wednesday. “He had a two-month head start on us. He loaned himself $250,000 and was able to grab early voters, but now he can’t.”

The winner of the runoff in the Orange County district will replace ex-Rep. Christopher Cox (R-Calif.), the new chairman of the Securities and Exchange Commission.

Campbell, the frontrunner throughout, had to battle Gilchrist from the right, second place finisher and former Assemblywoman Marilyn Brewer from the GOP left, not to mention 14 other candidates who grabbed a total of 54 percent of the vote from a meager 20 percent of registered voters.

“He feels good,” said Campbell campaign manager Jim Terry. “We had a lot of money dumped in this last week. … A total of almost $1.2 million was spent against him, most of it negative, and he withstood that.”

California-based Republican consultant Dan Schnur doesn’t expect Gilchrist to cause Campbell much of a problem in the runoff. But that doesn’t mean Gilchrist’s signature issue — illegal immigration — isn’t registering.

“In the narrowest sense, all that Gilchrist has done is slow Campbell by a couple of months,” Schnur said. “Having said that, this is an issue that hasn’t gone away, and it’s something that politicians in both parties need to pay close attention to.”

Brewer, who was endorsed by Sen. John McCain (R-Ariz.) and was reasonably well-funded, with more than $600,000 by Election Day, received 16.7 percent of the vote for a second-place finish. Attorney Steve Young, the top Democratic finisher, placed in the runoff with 8.9 percent of the vote.

Morgan said Gilchrist plans to keep the spotlight on what he believes is the federal government’s — and by extension the Republican Party’s — failure to enforce immigration laws and prevent illegal immigrants from streaming across the country’s southern border.

According to Morgan, Gilchrist was supported by just 6 percent of early and absentee voters but by 25 percent of those who voted on Election Day, statistics he cited as proof of his candidate’s growing support.

“Once folks met Jim Gilchrist and realized who he was, the numbers just flipped,” Morgan said. “I knew we had momentum, and was thrilled to see it show up in the actual balloting.”

Terry said the campaign is likely to fly below the radar until after the statewide Nov. 8 special election called by Gov. Arnold Schwarzenegger (R) to decide on a spate of voter initiatives.

Voter attention and the airwaves are likely to be consumed by that contest. Campbell, meanwhile, is not taking victory for granted.

“We will run a full-fledged campaign,” Terry said.