Republican Congressman Darrell Issa held a modest lead over Democratic challenger Doug Applegate with more than 183,000 votes counted Wednesday in a Orange and San Diego county race that has attracted national attention after Applegate’s unexpectedly strong primary increased the possibility of a upset.

In each of his seven previous re-election bids, Issa cruised to victory by 16 percentage points or more. But Republicans’ shrinking voter registration advantage in the district, which straddles the county line, and Issa‘s affiliation with the controversial campaign of Donald Trump buoyed Applegate’s candidacy.

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While Applegate was ahead in San Diego County, Issa’s advantage in Orange County gave him the edge. He dismissed the notion that his candidacy was hurt by Trump.

“Four years ago, voters in my district voted for Obama but crossed the line to vote for me,” he said. “So I have never been tied to the presidential candidate, Donald Trump or otherwise.”

Applegate, meanwhile, told supporters that the race was far from decided.

“It’s going to be a long night,” he said. “Maybe a long couple of days, but I want you to all hang in there. The fight isn’t over. Let’s throw Darrell Issa off the Hill.”

Issa, 62, is best known as a watchdog and critic of the White House. The Vista resident built that reputation during his four-year stint as chair of the House Oversight Committee, where he launched numerous investigations into the Barack Obama administration.

Applegate, 62, is an attorney and retired Marine Corps colonel making his maiden voyage into politics. The San Clemente resident supported Bernie Sanders in the primary and shares many policy positions with the former presidential candidate. He’s said he wants to bring his military expertise to Congress, particularly in terms of national defense and veterans issues.

In the primary, Issa won 51 percent of the vote and Applegate got 46 percent in a district that includes the Camp Pendleton Marine Corps base.

Through Oct. 19, Issa had spent $3.9 million to Applegate’s $975,000. But the challenger’s strong primary showing attracted a flood of independent expenditures from Capitol Hill Democrats and labor unions who added Issa to the list of House Republicans who could be vulnerable because of their support for Trump.

With $4.8 million spent on behalf of Applegate in independent expenditures — and just $69,000 in independent expenditures for Issa — Applegate and his backers were poised to spend 50 percent more on the race.

While he hadn’t spent his own money as of the Oct. 19 filing, Issa has plenty of personal funds on hand thanks in large measure to his former ownership of the car alarm company that produced the Viper security system. The Capitol Hill publication Roll Call has ranked him the wealthiest member of congress with a net worth of $255 million.

Issa has endorsed Trump, is a member of his National Security Advisory Committee and introduced him at a San Diego rally. But he has condemned Trump’s lewd open mic comments and has a different approach to dealing with illegal immigration than the presidential nominee.

Issa favors a guest-worker program to fill the many of the low-wage jobs now held by undocumented immigrants and has noted the a massive border will not address the people who enter the country legally but overstay their visas.

Unlike Issa, Applegate supports Obama’s executive orders enabling many undocumented immigrants to remain in the country legally. Applegate also supports a path to citizenship for those in the country without papers.

Contact the writer: mwisckol@ocregister.com