Rep. Brian Fitzpatrick (R-Pa.) talks during a town hall meeting in Bensalem, Pa., in August. (Tom Williams/CQ-Roll Call)

Brian Fitzpatrick has almost nothing in common with President Trump except for the “R” behind their names.

But in an election year that is all about Trump, that affiliation alone could cost the 44-year-old congressman his reelection in a seat key to Democrats’ strategy to win back control of the House.

So Fitzpatrick is campaigning as the anti-Trump, one of the few Republicans around the country to boldly separate himself from a president who remains wildly popular in his own party.

On a recent morning here, Fitzpatrick, a former FBI agent who left the agency to run for Congress in 2016, drove from a wealthy suburban end of his district to a grittier, blue-collar neighborhood to attend afternoon prayers at the North Penn Mosque, as he’s done many times since taking office. Afterward, he walked to the parking lot with an older man in a light-blue tunic and pale yellow skullcap, their arms around one another’s shoulders. Gazi Abdur Razzak, a Bangladeshi songwriter and a Democrat, called the young congressman “family.”

Fitzpatrick doesn’t have to say the president’s name — everything he does seems to be an implicit repudiation of Trump.

He’s taken some direct shots, too. He introduced legislation to require presidential candidates to release their tax returns — as Trump famously did not. He challenged Trump on Twitter to stop bashing the FBI — and braced himself for an attack from @realdonaldtrump that never came. He said Trump had been “manipulated” by Russian President Vladimir Putin.

Moreover, his policy résumé could easily belong to a Democrat.

He supports a carbon tax and voted against the Affordable Care Act repeal effort last year. He was against the White House’s travel ban on people from several Muslim-majority countries. He supports a path to citizenship for “dreamers,” the undocumented immigrants brought here as children. He opposed family separations at the border. He supports gun-control measures and has an F rating from the NRA. He didn’t vote for Trump in 2016 — he wrote in Mike Pence’s name.

Fitzpatrick can’t even explain why he is a Republican other than to say that his older brother, Michael G. Fitzpatrick, who previously held the seat, registered him as one when he was young.

“I have been asked by many Democrats here in the past year why don’t I change parties,” he said. “If I did that, I’d be doing exactly what I’m speaking out against, that labels matter. They shouldn’t matter.”

But, of course, that’s not how American politics work. The “R” behind his name automatically aligns him with Trump — the president has called the midterms a personal referendum, though he said won’t take the blame if the GOP loses — and a vote for Fitzpatrick is a vote for keeping the House in Republican hands. The race is rated by election experts as a toss-up.

“I think people like him. I know for a fact that Democrats like him,” said Larry Ceisler, a longtime Democratic operative in the state. “But he’s caught in a tough year. A lot of these voters who normally would have crossed party lines, I don’t know if they can do it.”

There are other challenges besides Trump. He’s in a fierce fight with a liberal, millionaire political outsider, Scott Wallace, who is outspending him nearly 5 to 1. The Republicans at the top of the ticket — the gubernatorial and Senate candidates — are down by double digits to the Democratic incumbents and could be a drag on Republican enthusiasm.

At a recent debate, Wallace criticized Fitzpatrick for being in the party of Trump.

“The tone starts at the top; the fish rots from the head. We need a more aggressive watchdog in Congress, not a lap dog,” Wallace said, according to the Bucks County Courier Times. “We have a president that is without shame, and we have a Congress that is without spine.”

National Democrats are spending lavishly, doing everything to make sure the Republican label sticks, hitting Fitzpatrick for his vote in favor of the tax cut bill — which ended the Affordable Care Act’s individual mandate — and accusing him of opposing preexisting-condition protections even though he voted to save the law requiring them.

“Brian Fitzpatrick’s words are just that — words,” said Evan Lukaske, a spokesman for the Democratic Congressional Campaign Committee.

Working in Fitzpatrick’s favor is that voter in Bucks County, which makes up the majority of his district, are known to split their ballots. In 2012, Mitt Romney lost to President Barack Obama by just two points in Bucks County, while Michael Fitzpatrick won by 13 points. In 2016, Hillary Clinton eked out a win here over Trump by less than a point while Brian Fitzpatrick beat his Democratic opponent by seven.

Yet it’s also the type of area that rides a political wave. In 2006, Michael Fitzpatrick was kicked out of office when Democrats took control of the House, only to win back the seat in 2010 when the Republicans regained the majority.

“It’s a tough race, but that district has been a tough seat historically for either side,” said Charlie Gerow, a Pennsylvania-based Republican consultant. “Fitzpatrick’s bipartisan approach to things fits the district. It’s not an ideological district, it’s a very flexible district.”

Pennsylvania’s 1st Congressional District (formerly the 8th) is one of the few that stayed mostly intact when the Pennsylvania Supreme Court ruled in January that the state’s gerrymandered district lines needed to be redrawn to more fairly represent the state. The District encompasses all of Bucks County, one of the vote-rich Philadelphia collar counties that are often looked to as the key to winning any statewide election here. It’s the archetypal majority-white, suburban area where Democrats struggled in 2016 and must win this year to flip control of the House.

But centrists are a dying breed even here — two of the moderate Republicans representing other Philadelphia suburbs, Charlie Dent and Ryan Costello, chose not to run for reelection because of the political climate. Fitzpatrick is on an island, and he knows it.

“The biggest threat facing our country, I think, is the shrinking of the center and the expanding of the wings,” he said, “and it’s going to destroy our country.”

That evening, in a Starbucks on the quaint Main Street in Doylestown, Jarid Metz, 28, a chemist and registered Democratic, shook Fitzpatrick’s hand and wished him luck.

Metz is a first-time midterm voter. He still doesn’t know who he’ll be supporting in November, but said he wouldn’t be upset with either choice. His biggest issue isn’t policy, but Washington politics.

“I feel like the way Trump acts gets in the way, but the extremes are pretty annoying, always at each other, both lying,” he said. “No one is willing to take a compromise.”

Fitzpatrick insists that he is.

“If the majority of members of a party take one view and I take another, I would think that would be something to be applauded, not ‘What’s wrong with you for being a part of that party?’ ” Fitzpatrick said. “It’s easy to attack people from the other party. It’s a lot harder to attack your own, and I do it all the time.

“It can be a very lonely place.”

At a senior expo in a new sliver of his district, an older man leaning on a cane clasped the congressman’s shoulder. “Where’s your tie?” he asked.

“I’m a man of the people,” Fitzpatrick said, smiling.

Russ Bohacci, 90, a lifelong Democrat, is no fan of Trump — he calls him “lousy” — but he supports Fitzpatrick because “he’s a human being.” He thinks Fitzpatrick has a “slim chance” of winning this year because he’s a Republican.

Standing in a small group, Barbara Vesay, 75, a Republican, told Fitzpatrick, “I hope it goes well for you.” She thinks that Trump “is trying to cure a lot of the evils that existed for years” and that Democrats need to “get off their high horse.”

It’s the type of crossover appeal that most politicians would dream of, but it may not be enough. And a loss by Fitzpatrick on Nov. 6 could signal a rough road for any vulnerable Republican.

“If on election night you see that Brian Fitzpatrick has lost,” said Christopher Borick, political pollster at Muhlenberg College, “it’s going to be a fantastic night for the Democrats.”