President Donald Trump threw his weight behind former Sen. John E. Sununu in the New Hampshire GOP Senate primary on Sunday, siding with the Republican establishment's preferred candidate over former Sen. Scott Brown, a longtime Trump ally who endorsed him before the 2016 New Hampshire primary.
The endorsement landed like a thunderclap in a race that had been quietly simmering between two former senators with very different relationships to the president.
Trump posted his endorsement on social media, calling Sununu an "America First Patriot" who "will work tirelessly to advance our America First Agenda."
John E. Sununu has my Complete and Total Endorsement — HE WILL NOT LET YOU DOWN. MAKE AMERICA GREAT AGAIN — ELECT JOHN E. SUNUNU.
The endorsement represents a significant political pivot. Sununu has spent years positioning himself against Trump and the America First movement.
In 2016, while Brown was backing Trump ahead of the New Hampshire primary, Sununu served as national co-chair of Ohio Gov. John Kasich's presidential campaign—a campaign that refused to support Trump as the party's nominee. In 2024, Sununu and his brother, former Gov. Chris Sununu, endorsed Nikki Haley as she battled Trump for the Republican nomination.
On the eve of the 2024 first-in-the-nation presidential primary, John E. Sununu penned an opinion piece in the New Hampshire Union Leader with a headline that left nothing to interpretation: "Donald Trump is a loser."
That history hasn't been forgotten by everyone. A group of MAGA activists responded to the endorsement on X:
The Sununu family openly mocked, degraded, and worked against the America First movement, the President himself, and the policies that energized New Hampshire voters.
They pledged to "continue and intensify our campaign opposition to the Sununu operation."
Trump's endorsement follows a coordinated push by Senate Republican leadership to clear the field for Sununu. When the former senator jumped into the race in late October 2025, he arrived with the backing of the National Republican Senatorial Committee. Sen. Tim Scott, the NRSC chair, declared that Senate Republicans were "all-in" for Sununu.
The Senate Leadership Fund, aligned with Majority Leader John Thune, moved quickly to frame Trump's endorsement as the final word:
John Sununu is the clear choice to be New Hampshire's next US Senator, and President Trump's critical endorsement has put an end to the primary.
The numbers back the confidence. Sununu more than doubled Brown's fundraising haul during the past three months. The latest public opinion polls show Sununu with a double-digit lead over Brown in the GOP primary.
Sununu responded to Trump's endorsement with gratitude:
I want to thank the President for his support and thank the thousands of Granite Staters who are supporting me.
Scott Brown isn't going anywhere.
The former senator—who served as U.S. ambassador to New Zealand during Trump's first term—spent over six months building grassroots support before formally launching his campaign in June 2025. He raised roughly $1 million during his first three months as a candidate.
In response to Trump's endorsement of his opponent, Brown struck a defiant tone:
I've always believed that the people of New Hampshire are the ultimate authority on our future, and they deserve a choice between candidates seeking to earn their support.
Brown framed his candidacy as mission-driven rather than career-driven:
I am running to ensure our America First agenda is led by someone who views this mission not as a career path, but as a continuation of a lifelong commitment to service.
My priorities for New Hampshire remain clear: a stronger economy, a secure border, reliable and affordable energy and better health care for our veterans. This mission has always been about you, not me. Let's keep working!
The September 2026 primary will determine whether Republican voters agree with party leadership—or whether they remember Sununu's past rhetoric.
The seat opened when Democratic Sen. Jeanne Shaheen announced she would retire at the end of this year rather than seek a fourth six-year term. Shaheen and Sununu have history—he defeated her in 2002, and she returned the favor in 2008.
With Republicans holding a 53-47 Senate majority, the New Hampshire seat represents both an opportunity and a risk. The state has trended purple in recent cycles, and Democrats see a genuine pickup opportunity.
Rep. Chris Pappas, a four-term congressman representing the eastern half of the state, is the clear front-runner for the Democratic nomination. He's already demonstrated formidable fundraising ability, outraising both Sununu and Brown combined during the fourth quarter of 2025.
Current polling shows Pappas topping Sununu by single digits and Brown by double digits in hypothetical general election matchups.
The NRSC's decision to back Sununu over the more Trump-aligned Brown reflects a cold political calculus. In a swing state like New Hampshire, electability concerns trump ideological purity.
Sununu brings institutional advantages: name recognition from his father's tenure as governor and chief of staff to President George H.W. Bush, his own three terms in the House and previous Senate service, and deep relationships with the state's Republican donor class. The fundraising disparity with Brown suggests those advantages are translating into tangible support.
For Trump, endorsing Sununu represents a willingness to prioritize winning the seat over settling scores. The man who called him a "loser" in print is now the president's chosen candidate. Politics makes strange bedfellows—and Senate math makes even stranger ones.
New Hampshire is one of several states where Republicans see opportunities to expand their majority. Georgia's Jon Ossoff is viewed as particularly vulnerable, making every competitive seat matter for the NRSC's 2026 strategy.
The grassroots MAGA opposition to Sununu presents a wild card. Whether that opposition translates into votes for Brown—or simply depressed turnout in the primary—could determine the trajectory of the race.
Brown's refusal to exit suggests he believes there's a path, endorsement or no endorsement. His argument is straightforward: the voters, not party leadership, should decide. It's a message that resonates with Republicans skeptical of top-down candidate selection.
Sununu now enters the primary with every institutional advantage imaginable: the president's endorsement, the Senate leadership's backing, a significant fundraising lead, and commanding poll numbers. The question is whether those advantages hold against a candidate who can credibly claim he stood with Trump when Sununu was calling him a loser.
September will provide the answer. Until then, New Hampshire Republicans face a choice between the candidate their party leaders want—and the one who wanted their party's leader first.
