Rep. Darrell Issa (R-Calif.) observes demonstrators massed across the street from his office in Vista, Calif., on May 30. (Mike Levin via AP)

Outside San Diego, a 14-year incumbent climbed atop the roof of his district congressional office to photograph protesters opposed to his support for a Republican health-care bill.

Just up the highway in Orange County, a 28-year incumbent mused about his belief in a conspiracy about a Democratic National Committee staffer slain in Washington last year.

And across the continent, in northern New Jersey, an eight-year incumbent faced a hostile crowd at a town hall, winning loud applause only when he denounced President Trump.

These are strange times for some longtime House Republicans. After years, sometimes decades, coasting to reelection in traditional GOP strongholds, these lawmakers find themselves under fire from angry constituents swept up in organized efforts to oppose Trump. And in some cases, they are already seeing Democratic opponents line up against them for an election 17 months away.

Collectively, Democrats are much more focused on dozens of seats held by relatively new Republicans who have never run into the head winds of midterm elections with their party’s president facing deep unpopularity.

(Peter Stevenson/The Washington Post)

But Democrats have also turned a powerful spotlight on a collection of veteran GOP lawmakers whose districts have changed underneath them, even while these districts continued, all the way to 2016, to reelect their representatives by wide margins.

There’s Rep. Dana Rohrabacher (R-Calif.), who told The Washington Post over the weekend that he hoped the conspiracy theory concerning the slaying of a DNC staffer might be true. First elected in 1988, Rohrabacher won reelection by almost 17 percentage points last fall, even as Trump lost the district to Hillary Clinton.

And there’s Rep. Leonard Lance (R-N.J.), who despite winning all five of his congressional races by more than eight percentage points is running as one of the most outspoken anti-Trump Republicans on Capitol Hill. That’s in large part because his district, in the state’s wealthy, well-educated suburbs, swung from favoring Mitt Romney by more than six percentage points in 2012 to backing Clinton over Trump last year.

History would seem to favor these entrenched Republicans as familiar figures in their districts. But history has also shown that when the House majority changes hands, a large chunk of the losses tends to come from these members of the old guard. In some cases, they lose touch with their districts over time. Just as often, they have never run modern campaigns and their political operations have grown too rusty to contend with a shifting political landscape.

The most famous of all was the stunning defeat of Rep. Thomas Foley (D-Wash.) in 1994, the first sitting House speaker to lose reelection, during a wave election in which Republicans won 54 seats and reclaimed the majority for the first time in 40 years. That year also brought down the sitting chairmen of the Ways and Means Committee and the Judiciary Committee.

Twelve years later, as Democrats swept back into the majority, their victories included the defeat of a 30-year incumbent from Iowa, Republican Jim Leach, and a 26-year veteran from South Florida, E. Clay Shaw Jr., who two years earlier had won with 63 percent of the vote. And in 2010, en route to a 63-seat gain and the majority, Republicans claimed the political scalps of the Democratic chairmen of the Armed Services, Budget and Transportation committees among the veterans swallowed up by that wave.

Veterans of those prior waves wish that their incumbents had gotten as early a scare from the opposition party as Republicans are feeling this cycle. The GOP has fought like mad just to hold seats in deeply red districts in two special elections, with two more on the horizon. That sort of warning sign did not come until well into 1994, 2006 and 2010.

Republicans think these elections, plus protests at town halls, will get their longtime incumbents prepping for next year’s potential climate. “We’ve been pretty aggressive with making sure they’re ready,” said Matt Gorman, communications director for the National Republican Congressional Committee.

There are 40 House Republicans sitting in districts where Trump received less than 50 percent of the vote; 23 of those districts actually favored Clinton. Of those 40 lawmakers, 14 will have served at least a decade by the time of the November 2018 midterms.

Out of the 14 GOP veterans in vulnerable districts, only Rep. Darrell Issa (R-Calif.) has faced a tough campaign in the past five elections, having fought to win a bitter contest last year by less than one percentage point.

“None of them have faced credible, well-funded challenges in the last decade,” wrote David Wasserman, editor for House races at the independent Cook Political Report. “And ironically, this could make them more vulnerable in a wave scenario than less senior but more recently battle-tested GOP colleagues.”

Clinton even weighed in on the opportunity this week at the annual Code Conference in Rancho Palos Verdes, Calif.

“Let’s look at the House,” she said. “We have to flip 24 seats, okay? I won 23 districts that have a Republican Congress member. Seven of them are in California, Darrell Issa being one. If we can flip those, if we can then go deeper into where I did well, where we can get good candidates, I think flipping the House is certainly realistic. It’s a goal that we can set for ourselves.”

Democrats point to two recent moves by senior Republicans to suggest that shaky political instincts are at work within the GOP. On Tuesday, Issa, the former high-profile chairman of the House Oversight and Government Reform Committee, had a brief encounter with hundreds of protesters outside his office, leading him to retreat indoors and then up to his roof to take pictures.

Issa told the local news media that he had wanted to address the group but was rebuffed. Still, the incident became something of a laugh line on the local TV news broadcasts.

Earlier this spring, Rep. Rodney Frelinghuysen (R-N.J.), the new chairman of the powerful Appropriations Committee, sent a fundraising letter to a local banker that included a handwritten note letting him know that one of the “ringleaders” of liberal activists worked for him. That prompted accusations that the 26-year incumbent, who regularly coasts to reelection, was threatening a constituent.

GOP strategists brushed off Issa’s rooftop move as a goofy incident that will not resonate with voters. They think Frelinghuysen’s family lineage, dating to the Continental Congress, will insulate him from any Trump fallout.

Republicans do have time to shore themselves up — but that also means these veteran lawmakers have time to make more mistakes.

“The biggest advantage for these Republicans is that the election is still 18 months away and there is still time to batten down the hatches,” Wasserman wrote. “But sometimes, errors cascade.”

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