Former Republican Senator John E. Sununu and Democratic Representative Chris Pappas secured decisive victories in New Hampshire’s Senate primaries on Tuesday, setting the stage for a closely contested general election in November. The seat is open as incumbent Senator Jeanne Shaheen (D-New Hampshire) retires after serving three terms.
Despite lower national attention compared to other pivotal Senate races, New Hampshire’s contest has attracted notable interest due to its history of narrow margins and shifting political dynamics. A recent University of New Hampshire poll from August showed Sununu leading Pappas 45 percent to 43 percent. The nonpartisan Cook Political Report currently classifies the race as “Lean Democrat.” No Republican has won a U.S. Senate seat in New Hampshire since 2010, although recent Democratic victories have been by slim margins, exemplified by Senator Maggie Hassan’s 2016 win by approximately 1,000 votes.
The primary outcomes highlight several key developments. Voters in both parties appear to embrace political families. The contest underscores the enduring influence of the Sununu political dynasty, which dates back to John H. Sununu’s election as governor in 1982. John E. Sununu served in the House for three terms and the Senate for one before losing his seat to Jeanne Shaheen in 2008. Meanwhile, Stefany Shaheen, daughter of the retiring senator, won the Democratic primary for the House seat vacated by Pappas, sparking criticism from opponents who said her candidacy rode on her family name—a charge she denied.
Former President Donald Trump’s endorsements played a significant role across New Hampshire’s primaries. Trump backed Sununu despite past criticisms by the candidate and campaigned against former Senator Scott Brown in the Republican primary, where Sununu prevailed convincingly with over 68 percent of the vote. All Republican candidates endorsed by Trump for U.S. Senate in 2026 secured their nominations, though several Trump-backed House and gubernatorial candidates were unsuccessful. Trump also endorsed Anthony DiLorenzo for Pappas’s open House seat, with DiLorenzo winning the Republican nomination.
On the Democratic side, the primary saw a strong showing from Karishma Manzur, a scientist and recent member of the Democratic Socialists of America, who garnered around 33 percent of the vote despite limited fundraising and low name recognition. Her performance follows a broader trend of democratic socialists making inroads in competitive primaries, including notable victories nationally.
Democratic primary turnout surpassed Republican participation, with more than 150,000 voters casting ballots compared to approximately 108,000 in the GOP primary. Although New Hampshire has more registered Republicans than Democrats, the state’s sizable unaffiliated voter base and tradition of ticket-splitting make it difficult to predict the general election outcome based solely on primary turnout.
In related races, former Governor Kelly Ayotte easily won the Republican gubernatorial primary and will face Democrat Cinde Warmington in November. Ayotte is considered a strong candidate, with polls indicating a double-digit lead. Republicans hope Ayotte’s popularity will boost Sununu’s Senate bid, though New Hampshire voters have historically elected candidates from different parties in statewide contests.
As November approaches, the New Hampshire Senate race remains competitive and emblematic of the state’s fluid political landscape, with both parties vying for an open seat that could influence control of the Senate.