LOWER MACUNGIE TOWNSHIP, Pa.—Two years ago, working-class voters’ anger over the high cost of living helped carry Republican Ryan Mackenzie into Congress by a 1% margin. Now, those same pocketbook issues threaten to unseat the freshman incumbent, who is fighting for his political survival in a swing district.

Mackenzie, 44 years old, hopes to persuade voters to give him another term by touting results he has delivered and attacking his Democratic opponent. He is also keeping close ties to President Trump, whose falling statewide approval ratings contrast with pockets of deep support in the 7th Congressional District, which Trump won in 2024.

The race is one test of whether Republicans can hold on to the white working-class voters who flocked to the party here and nationally after Trump’s first run in 2016. Some 45% of district residents 25 and older fall into this category, defined by those without a four-year college degree, and Democrats are betting that higher prices will pry them loose.

Rallying volunteers before a recent day of door-knocking, Mackenzie emphasized the stakes: “When you win by 1%, literally everything you do could have been that difference.”National party leaders are eyeing voters like Jim Koch, who farms 250 acres near Easton, Pa., and drove a truck after high school. A Democrat, he voted for Trump in 2024, but said he is now squeezed by higher costs for diesel, chemicals and fertilizer. “It’s been a total slap in the face,” he said, taking a break from a 15-hour day harvesting corn.

Democrats’ answer here is Bob Brooks, 53, a first-time candidate who spent two decades as a Bethlehem, Pa., firefighter, leads the state firefighters’ union and runs a lawn-care business. The goateed Brooks lacks a college degree and pitches himself as someone who can relate to the working class. To avoid paying $175 to fill his diesel truck, he said, he drives his wife’s Kia Telluride instead.

“That’s what everyone’s worried about,” Brooks added of fuel prices. “They’re blaming Ryan Mackenzie, and I agree with them.”Some Republicans are also linking Mackenzie—and his ties to Trump—to higher prices for gas, groceries, heating oil and housing in the district.

“He tends to follow the Trump line,” said Rob Manns, a Republican at a fire-station open house in Lower Macungie Township where Mackenzie chatted with voters. Facing higher electricity bills, Manns installed solar panels and a high-efficiency gas furnace last fall, but he said others are struggling.

As a 100-foot ladder reached skyward and firefighters passed out hot dogs, Manns said he is considering voting for Brooks.

Three Pennsylvania Republicans are defending closely watched U.S. House seats in heavily white, working-class districts. The Wall Street Journal’s election tracker rates two as tossups and Mackenzie’s as “lean Democrat.”Brooks led Mackenzie 45% to 40% in a Franklin & Marshall College poll last month. The margin of error was 5.8 percentage points and about 15% of respondents said they were undecided.

Around 25% of respondents in the district said Trump was doing an “excellent” or “good” job. The economy was their top concern, and 62% said Trump administration policies had hurt rather than helped them.

“The public’s pointing the finger at the president for these higher prices and the cost of living, and these candidates are carrying that weight upon their back,” said Chris Borick, a Lehigh University political-science professor.

The 7th district spans blue-leaning cities like Allentown and Bethlehem, suburbs where tidy developments have replaced dairy farms, the right-leaning Pocono Mountains, and mill towns that never recovered from lost manufacturing. Housing costs have climbed, partly because of New Jersey and New York transplants, some commuting to New York City.

In an interview, Mackenzie said he had brought $160 million in federal funding to the Lehigh Valley for healthcare, manufacturing and affordable-housing projects. He backed legislation that cut taxes on overtime, tips and Social Security, while helping to lower prescription-drug costs.

“We passed historic tax reform that put more money back in people’s pockets, froze in those lower rates for individuals and small businesses,” Mackenzie said.

Supporters like Jim Shafer, a Republican from rural Carbon County, Pa., who works in cybersecurity, plans to vote for Mackenzie again. “I think he’s more competent and a better administrator,” Shafer said. “What I would hope for as far as economics goes is that he prioritizes our district and works for middle-class families.”Brooks supports Medicare for All, raising the minimum wage and letting teachers and first responders buy a first home with no down payment. He recently rallied retirees at the United Steelworkers hall in Bethlehem alongside Jon “Bowzer” Bauman of the 1970s band Sha Na Na.

At 79, Bauman is stumping for Democrats on preserving Social Security and other seniors’ issues. Playing a rented electric piano, he closed with “DANG-a-DANG-DANG DING-DONG-DING vote for Bob Brooks!”A few blocks away at the Central Moravian Church food pantry, coordinator Connie Pierce said Saturday visits by people seeking assistance have risen to at least 65 people, from 40 last year, following cuts to the Supplemental Nutrition Assistance Program, or SNAP.

Pierce, a Democrat, said she sent notes to Mackenzie, including from the Grand Canyon, to try to get his support. When Brooks showed up to volunteer, he won her vote.

Tammy Lettich, a home health aide and independent voter, left with ham-and-cheese sliders, green beans and zucchini for her disabled client. A Pentecostal, Lettich said she might vote for Mackenzie, because she opposes abortion and transgender rights.

Mackenzie, meanwhile, has attacked Brooks as being controlled by establishment Democrats. One of his campaign ads accuses Brooks of borrowing more than $160,000 from his family and not paying it back.

“Bob Brooks is not only a far-left individual, but he is ethically compromised,” Mackenzie told volunteers at his Allentown campaign office, papered with campaign signs, before they headed out to knock on doors and he left for the Macungie firehouse.

An attorney for Brooks said last month that Brooks made a payment to resolve the family dispute. “He’s manipulating these ads to try and assassinate my character and it’s not working,” Brooks said in an interview.

About $16 million has been spent on ads in the race since the May 19 primary, $10 million of it in support of Mackenzie, according to ad-tracking firm AdImpact.

Near the Poconos, yard signs for Mackenzie sit alongside ones reading, “No Data Centers.”In towns like Palmerton, Pa., where a zinc plant once employed thousands, people feel gas prices acutely because they drive longer distances to work, the grocery store or doctor.

Residents there scoffed at the idea of voting for a Democrat. At Joey B, known for its lobster bisque and an old bullet hole in a wall, owner Chip Solt traced higher costs to Covid-19 disruptions, rather than Trump policies. Solt, who joined the Marines out of high school, said he doesn’t get “why we’re picking a fight with Canada,” but he is voting Republican.

Joe Lach, a Republican and retired sales representative for a logistics company, said over shrimp tacos and a Dewar’s that he credits Trump with lowering prescription-drug costs, and he supports the war with Iran.

“Everybody wants to vote Democrat—‘the blue wave,’ or whatever,” said Lach, who backs Mackenzie. “What are they offering that’s going to change your way of life? So far, I haven’t heard anything.”To Koch, the farmer near Easton, Pa., the choice isn’t straightforward. Asked whether he would back Mackenzie on Nov. 3, he replied, “Oh, man, I don’t know.”