A GOP state lawmaker will be sworn in to represent a reliably Republican congressional district, a day after withstanding a strong third party showing by an opponent of illegal immigration.

California state Sen. John Campbell was elected Tuesday with less than 50 percent of the vote to succeed Republican Christopher Cox, who represented the Orange County district in the House for 17 years before resigning to head the Securities and Exchange Commission.

"We didn't take anything for granted, but you've got to be ready to win," said Campbell. He was to be sworn in Wednesday in Washington.

In unofficial returns Tuesday with all precincts reporting and absentee ballots counted, Campbell received 41,450 votes, or 45 percent. Democrat Steve Young had 25,926 votes, or 28 percent.

Third-party challenger Jim Gilchrist, co-founder of the Minuteman Project border patrol group, was a strong third with 23,237 votes or 25 percent of the vote.

"Illegal immigration is the overwhelming issue in Orange County, and that's why he was able to come out of nowhere, because it was the perfect issue for Gilchrist to run on," political consultant Scott Hart told the Los Angeles Times.

Gilchrist, a former Republican running under the American Independent Party banner, had hoped his showing could push federal immigration policy to the forefront in next year's congressional races and influence the 2008 presidential campaign.

Many in the district, located about two hours from Mexico's border, have been frustrated with the growing population of illegal immigrants.

"Our cause is not over, nor is my aspiration for my political career," Gilchrist told the Times.

Campbell acknowledged the immigration debate but said "it's not the only issue, and I think that's the key message here."

Campbell, a conservative on such issues as abortion and taxes, breaks with President Bush on the administration's guest-worker plan. The president wants to catch more foreigners crossing the border while increasing the number of temporary work visas for those who will take jobs that Americans are unwilling to fill.

Campbell believes securing the borders should be the first order of business before considering a guest-worker program.

The Minuteman Project made headlines this spring when hundreds of volunteers turned out to patrol the Mexican border in Arizona. Critics expressed fears of vigilantism, but there were no reports of serious violence.