PLYMOUTH, N.H. — Chris Pappas has been seen as Democrats’ presumed Senate nominee in New Hampshire since he entered the race more than a year ago.

And for most of that time, the four-term congressman has also been viewed as a slight favorite to hold the seat of retiring fellow Democrat Jeanne Shaheen in a state that hasn’t elected a Republican senator since 2010.

Democrats looking to flip the Senate have expanded the battleground map into red states such as Iowa and Ohio. But to win the majority, they’d need to hold their own seats like New Hampshire, where polls show a tight contest between Pappas and the Republican front-runner, former Sen. John E. Sununu.  

Inside Elections with Nathan L. Gonzales shifted its rating of the race Thursday from Tilt Democratic to Toss-up. 

“It’s a building block that Democrats can’t afford to toss aside,” Pappas said in an interview here last week. “If we can’t hold the Senate seat, then the math just doesn’t work in other states.”

While Pappas and Sununu have appeared focused on the general election, both first have to contend with primaries Tuesday. Sununu is facing off against another former senator, Scott P. Brown, who previously represented Massachusetts, while Pappas faces biochemist Karishma Manzur, a political newcomer.

A University of New Hampshire poll released late last month delivered a jolt to the Democratic race when it showed Manzur’s support rising. Pappas led her, 47 percent to 34 percent, a margin of 13 points. The June version of the poll found him up 24 points over Manzur. 

But the Pappas campaign soon countered with internal polling, reported first by Semafor, that showed the congressman taking 71 percent of the Democratic primary vote to Manzur’s 15 percent. 

In the interview, Pappas pivoted away from the UNH poll, saying that Democrats needed a candidate who has “shown they can beat MAGA candidates.” Pappas currently represents the battleground 1st District, a perennial Republican target. His GOP opponents have included Karoline Leavitt, the recently departed White House press secretary who challenged him in 2022. 

“More than anything, Democrats want to win, and they want checks and balances on this administration, and we can deliver that by winning this Senate seat,” Pappas said.

Before his election in 2018, the 1st District, which covers the eastern part of New Hampshire, regularly flipped between the two parties. In the House, Pappas has been largely aligned with the Democratic mainstream, although he split more with his party in 2024 and 2025 compared with his early years in Congress, according to CQ Roll Call’s Vote Studies. He said he was particularly proud of the work he’s done in the House on veterans issues.

Pappas has the support of national Democratic groups, as well as both New Hampshire senators, Shaheen and Maggie Hassan. If elected in November, he would be the first openly gay man to serve in the Senate.

Manzur has campaigned on her outsider status, hoping that the same forces that have elevated progressive candidates in Democratic primaries this cycle will help push her toward the nomination.

Her backers include former New York Rep. Jamaal Bowman and several current and former New Hampshire legislators, but she hasn’t gotten the kind of national progressive support that have helped elevate progressive candidates in competitive primaries this year. 

Federal records also show her raising $415,000 through July 29, compared with $15.4 million for Pappas. The congressman entered August with about $4.3 million on hand to $104,000 for his primary rival. 

Manzur has criticized the outside money pouring into the state and said the Democratic establishment hasn’t learned how to respond to voters after losing to Donald Trump two years ago. 

“The money in politics is a root cause of the problem,” she said in an interview.  

For Republicans, New Hampshire remains a bright spot in a year in which they have relatively few offensive opportunities. In Sununu, they have a candidate who served three terms in the House and a term in the Senate, before he lost to Shaheen in 2008. His family is well known in the state, as his father, John H. Sununu, served as New Hampshire governor and later as chief of staff to President George H.W. Bush, while his brother Chris Sununu served four terms as governor before opting not to seek reelection in 2024.

The late-August UNH poll found Pappas and Sununu in a statistical tie among likely voters. Forty-five percent said they would vote for Sununu, while 43 percent picked Pappas. Five percent would vote for someone else and 7 percent were undecided. 

“Poll after poll shows that Granite Staters are fed up with Party Line Pappas being a rubber stamp for Democrats’ radical agenda and they are ready to elect John Sununu in November,” Samantha Cantrell, a spokeswoman for the National Republican Senatorial Committee, said in a statement.

Among the reasons for GOP optimism about Sununu’s candidacy could be the presence of another high-profile Republican on the November ballot. 

“A strong performance by Gov. Kelly Ayotte at the top of the ticket may also be giving Sununu a boost,” Inside Elections wrote in a recent analysis of the race.  

Republicans will likely attempt to tie Pappas to more progressive candidates, despite his more centrist disposition. A strong showing by Manzur on Tuesday could give the GOP an opening for such attacks, according to Andrew Smith, the director of the UNH Survey Center. 

“Even though Pappas hasn’t been identified with [the far left] in the past, appearance is more important than reality. That’s a weakness that I think I would see for Pappas, and it’s almost out of your control,” he said.

But Pappas said that in a state with a savvy electorate and a large proportion of independent voters, he understands voters’ priorities and what it would take to keep the seat in Democrats’ grasp.

“Voters will want change in Washington,” he said. “You’re not going to get that with John Sununu, but that’s something that is important for my candidacy.”