There are growing signs that veteran Rep. Darrell Issa, R-Vista, could be headed for an election dogfight.

Issa has breezed to re-election seven times since taking office in 2001, but the landscape is different this time.

His support for Donald Trump could undermine this year’s bid. The Republican edge in his two-county district’s voter registration is shrinking. And his Democratic opponent’s background as a Marine colonel holds particular appeal in a district that includes and surrounds Camp Pendleton.

In the 2012 and 2014 primaries, Issa prevailed by at least 30 percentage points. In June, he beat Democrat Doug Applegate by a relatively modest 5.3 percentage points. That’s less than the GOP’s 8.4-point advantage in voter registration – an advantage that has shrunk from 10.7 points since the beginning of the year.

Applegate’s primary performance came despite much weaker name recognition and despite being outspent by Issa, $740,000 to $50,000.

Yes, by nearly 15-1. That’s according to Federal Election Commission tallies.

Applegate, a San Clemente resident, raised just $58,000 for the primary but his relatively strong showing is attracting plenty of attention.

From the primary until the end of June, he raised $128,300 from donors who now believe he has a chance. Additionally, the primary results prompted the Democratic Congressional Campaign Committee to do polling in the district, which it previously had written off.

Polling results announced by an interested party should be read with a dose of skepticism. That said, the committee reported that its survey found the candidates deadlocked at 43 percent. And that Applegate led by 32 percentage points among independent voters.

Unaffiliated voters account for nearly a quarter of the district’s electorate, and independent candidate Ryan Glenn Wingo, who received nearly 4 percent of the primary vote, will not be on the November ballot.

The polling and Applegate’s strong June fundraising persuaded the Democratic committee to put Applegate on a watch list of 10 “emerging” Republican districts that could be moved to their tally of targeted GOP seats, which now includes 48 House districts nationwide.

Issa and Trump

Issa is best known for his rigorous criticisms while chairman of the House Oversight Committee of the Obama administration. But the biggest factor in his re-election bid could be Trump.

Democratic turnout was proportionately bigger than usual in the state’s primary, to a large extent because Democrats had a competitive primary while the GOP contest was settled. But Trump is scaring off some Republicans – from the two former President Bushes on down to everyday voters – and many experts expect that to suppress GOP turnout in November.

Trump’s low likability rating could rub off on Issa, who introduced Trump at a San Diego rally, was a Trump delegate to the Republican National Convention and who spoke supportively of Trump during his visits with California, Illinois and North Carolina convention delegations.

“Voters will hold Issa accountable for his partisanship and his stalwart support for Trump,” said DCCC spokeswoman Barb Solish.

One certainty is that Issa won’t lack for campaign funds. He’s the wealthiest member of Congress, with an estimated net worth of $357 million, and has a campaign balance of $3.8 million. Applegate campaign manager Robert Dempsey wouldn’t specify his candidate’s budget, but said $1 million was “in the neighborhood.”

Twenty-six percent of the district is in Orange County, which accounts for the most heavily Republican portion.

Issa campaign spokesman Calvin Moore dismissed the idea that Trump is a drag on his candidate, noting that both parties’ presidential nominees are unpopular and that Issa is running on his own record.

“Congressman Issa won an actual election just a few weeks ago by more than 10,000 votes, and we have every bit of confidence he’ll do it again in November,” Moore said.

Contact the writer: mwisckol@ocregister.com