Control of the House of Representatives could come down to four pivotal battleground races in Pennsylvania.

With an increasingly limited map of competitive seats, both Democrats and Republicans are emphasizing the importance of these campaigns, which are about to see a flood of money and investment from both sides.

Some of that has already started, including from Gov. Josh Shapiro, who is on a party-building kick while facing a re-election bid that, as of yet, is not expected to be particularly competitive. A potential 2028 presidential contender, Shapiro has emphasized these four races, making primary endorsements in each contest and signaling he will be deeply involved in them as November nears. Help the battleground Democrats win, and Shapiro will be able to tell Democratic presidential voters about how he helped the party re-take the House and defeat a broad spectrum of Republican House members. Fall short, and his political strength will come under further scrutiny.

And there’s the Donald Trump factor, too. Pennsylvania — a state critical to his 2016 and 2024 presidential victories — is one of his most-trafficked campaign stops. Republican victories, including by one of his closest congressional allies, would bolster his own political strength amid what is shaping up as a difficult election cycle for the GOP. Unlike Shapiro, though, Trump has yet to signal how big a role he will play in these contests.

Tuesday’s primaries locked in the cast of characters in these districts, though most of the matchups were virtually assured beforehand.

In Pennsylvania’s 1st District, Rep. Brian Fitzpatrick — one of the only congressional Republicans who won a district carried by then-Vice President Kamala Harris in 2024 — will face Bucks County Commissioner Bob Harvie. In the 7th District, first-term Rep. Ryan Mackenzie will face state firefighters union head Bob Brooks in the state’s swingiest district.

In the neighboring 8th District, another first-term Republican, Rep. Rob Bresnahan, will face-off with Scranton Mayor Paige Cognetti. And in the state’s 10th District, Rep. Scott Perry, the one-time head of the House Freedom Caucus, will face former newscaster Janelle Stelson in a rematch of a 2024 contest Perry narrowly won.

NBC News spoke with more than a dozen Pennsylvania political operatives, national strategists working on the races, and candidates running in them. The picture that emerged was of a Democratic Party eager to zoom in on a tightly clustered group of pick-up opportunities and tag-team the races with Shapiro, while Republicans, aware of the challenges that lie ahead, hope that their battle-tested incumbents can withstand the onslaught. And the candidates from both sides, meanwhile, are portraying themselves as above Washington, D.C., partisanship and in-touch with working-class concerns.

“The math is simple: Democrats can win back the House by flipping four seats in Pennsylvania,” Democratic Congressional Campaign Committee spokesperson Eli Cousin said in a statement, calling the four Republicans “uniquely vulnerable” and touting Shapiro as “a political juggernaut at the top of the ticket.”

A Democratic operative close to multiple potential 2028 contenders told NBC News they are “feeling very confident” about the handful of battleground House races in Pennsylvania. But should Democrats fall short in any number of these contests, this person said “what a problem that would be.”

“Not just for Democrats, because we need Congress, but because this was supposed to be the shining example of candidate selection and the governor getting in early and all that stuff,” this person, who requested anonymity because they are not allowed to speak with the media, said.

Republicans who spoke with NBC News acknowledged the challenge of facing Shapiro’s ticket in a state where he enjoys high approval ratings and defeated his 2022 opponent, state Sen. Doug Mastriano, by 15 points. And that is in addition to a tough national environment where Trump’s approval numbers are sagging and voters have expressed dissatisfaction with the economy and his handling of the war in Iran.

“In addition to facing uphill national tides against them, they also have to deal with the fact that Josh Shapiro is going to have unlimited money,” a former Trump campaign official with ties to the state said, adding: “Which means that instead of spending money on his own re-election, he’s going to be spending money targeting” Perry, Mackenzie and Bresnahan.

The former Trump campaign official said the candidate most likely to feel the most heat from Shapiro is Perry, who was closely involved with Trump’s effort to overturn the 2020 election and defeated Stelson in 2024 by a few thousand votes. This person said if Shapiro makes it “his mission” to defeat Perry as outside spending floods the district, it will be difficult for the congressman to prevail.

“My guess is the number one thing he talks about is getting Scott Perry so that he can call up any national donor and say, not only did I flip two freshman districts, but also the former head of the Freedom Caucus is gone,” the person said.

In a primary night address to supporters on Tuesday, Shapiro noted Pennsylvanians “have a lot of power and a lot of responsibility this year.”

“You also deserve leaders in Congress who will focus on getting stuff done for you — not going to D.C. to say yes to whatever they’re told, no matter how much it hurts Pennsylvanians,” he said, adding, “Think about what it will look like, after we flip four seats here in Pennsylvania and win all across this country in November, to have a Congress that actually fights for us.”

The districts cover the Lehigh Valley, Wilkes-Barre/Scranton through the Poconos, south-central Pennsylvania and a slice of suburban Philadelphia. The candidates have stressed bipartisanship in their messaging — and even some Republicans Shapiro is targeting have refrained from criticizing the governor.

In interviews, Harvie said one of the facts he was most proud of in his time as commissioner was the high rate of bipartisan votes he has taken. Cognetti, who ran for mayor as an independent, discussed the electorate in her city and district favoring leaders who “don’t govern in a partisan way.”

Stelson said she was “the nonpartisan voice of this area for more than 30 years” in local TV news, adding, “for me, it doesn’t matter which party, Democrat, Republican, you will represent everyone, the independents, and I want them to know I’m listening, and I’m going to be doing the work.”

On the Republican side, Bresnahan talked up his work on constituent services and membership in the Problem Solvers’ Caucus. He touted bipartisan work on his website and, in a working-class district, was particularly proud of being one of a small handful of Republicans to win the backing of the American Federation of Government Employees, the largest federal employee union.

“I’m one of only two Republicans in the Commonwealth of Pennsylvania that they’ve endorsed, because I’m willing to work across the aisle,” he said.

Republicans see Bresnahan’s work on labor issues as one of his best calling cards in what will be a difficult race. They’re hopeful that a bruising primary in the neighboring district can boost Mackenzie’s chances, while Fitzpatrick’s proven ability to win in a tough political environment will serve him well.

“I don’t think anyone’s under any illusions that it’s gonna be easy,” a national Republican strategist working on the races said. “Everyone’s very clear about the fact that we’re looking to defy history here.”

Democrats in Pennsylvania are coalescing around a midterm message focused on the economy and, more recently, corruption. In his primary night address, Shapiro mentioned “corruption” in Washington at least a dozen times. Both Stelson and Cognetti have framed themselves as corruption-fighters in their runs.

Cognetti targeted Bresnahan for a series of stock trades he made in office, including when he sold up to $130,000 in stocks in companies that manage nearly half of all Medicaid enrollees before voting to make cuts to the program. Bresnahan said financial advisers manage his portfolio and he gave them no instructions on what to buy, sell or hold.

“Part of his platform was on banning congressional stock trading, and he immediately became one of the most active stock traders in Congress,” Cognetti said. “I know from conversations throughout the district, even before we decided to run, that folks know him as the stock trader. … Folks don’t want to see their local elected officials personally profit off of their public office.

Bresnahan said he is “actually excited for the legislation, any piece of legislation that provides some kind of guidance for people that had careers before coming to Congress.”

“Personally, I don’t think that the mayor of Scranton can run on her record,” he said. “They can’t assault me on my actual voting record, so they’ve resorted to character assassination.”

On Trump’s role in the races, Republicans said most are of the mindset that it’s better to accept Trump’s help and gain the benefits of his appearance and support, since most will be tagged with any downside of an alignment with Trump regardless of if he is involved.

“President Trump and House Republicans have been successful in Pennsylvania by being laser-focused on lowering costs, improving community safety, and strengthening American manufacturing,” National Republican Congressional Committee spokesperson Reilly Richardson said in a statement, adding, “Republicans are united and ready to win this November.”

Asked if he would like to see the president campaign for him, Bresnahan said, “what’s so important is that we have a relationship with the administration and Cabinet officials.”

“So regardless of who is in power in the state Legislature or in the presidency, the member of Congress needs to work with everyone, and we’re certainly going to continue to work with the president,” he said. “And should the president choose to come back to Northeastern Pennsylvania, we’re absolutely going to welcome him.

On the other hand, Democrats are excited about Shapiro’s personal involvement.

“We’re so excited to be working with him, and honored that we were his first of the cycle in terms of endorsements,” Stelson said, adding that Shapiro introduced her at her campaign launch.

Republicans though have held their fire and even praised Shapiro, as Fitzpatrick did ahead of the governor endorsing Harvie.

“I honestly haven’t given much thought into the implications of what Josh Shapiro may or may not do,” Bresnahan said, adding that he has a good relationship with Shapiro’s federal legislative affairs team. “The governor is well entitled to endorse whoever he thinks is right for his fit, but we’re still going to work together, and I’m going to work with this team, because at the end of the day, the people of Northeastern Pennsylvania deserve representation at the federal level that aligns with their ideological beliefs.”

Both sides are gearing up for the political world to zero in on these races. This fall marks the first election cycle since Trump’s 2016 bid for the presidency that Pennsylvania won’t feature a competitive Senate race or presidential contest on the ballot.

“If we protect Pennsylvania, I think that we feel we are well on our way to protecting our House majority,” the national Republican strategist added. “A lot of people are going to be looking to Pennsylvania on election night.”