Washington — Former GOP Sen. John Sununu and Democratic Rep. Chris Pappas will face off in November after winning their primaries for U.S. Senate on Tuesday night, CBS News projects.

Democratic Sen. Jeanne Shaheen’s decision not to seek reelection kickstarted the competitive race for an open seat in the Granite State, which could be key to determining which party controls the Senate. As her successor, Shaheen endorsed Pappas, who is one of the state’s two representatives in the House. But Pappas faces a formidable opponent in a Republican with widespread name recognition in the state, hailing from a political family that’s spent decades in its leadership.

Sununu, 61, represented New Hampshire in the House and Senate for more than a decade, before he was ousted by Shaheen. The son of former Gov. John H. Sununu and brother of former Gov. Chris Sununu, his name carries significant weight in New Hampshire. In the GOP primary on Tuesday, he defeated former Sen. Scott Brown, who represented Massachusetts in the Senate from 2010 to 2013.

Pappas, 46, has represented New Hampshire in the House since 2019, where he’s a member of the bipartisan Problem Solvers Caucus. On the campaign trail, he’s billed himself as an independent voice for New Hampshire. And he defeated a progressive candidate, medical scientist Karishma Manzur on Tuesday, despite a number of victories by insurgent Democrats elsewhere in the country this cycle.  

With 53 Republicans in the Senate, Democrats would need to flip four seats to gain control of the upper chamber, while defending a handful of seats, like in New Hampshire.

Although Republicans have controlled New Hampshire’s governor’s mansion since 2017, the state hasn’t elected a Republican to the Senate since 2010, and a Republican hasn’t won in the state at the presidential level since 2000. But Pappas has acknowledged that the race is “highly competitive,” telling CNN last month that “it will continue to be tight until the very end.”

Despite Democrats’ recent successes in Senate and presidential contests, New Hampshire is far from deep-blue territory, with elections often decided by narrow margins. President Trump lost by 2.8 points in 2024 and 0.4 points in 2016, and Democratic Sen. Maggie Hassan defeated Republican Kelly Ayotte — now the governor — by roughly 1,000 votes a decade ago.

Pappas has sought to tie Sununu to Mr. Trump, who endorsed the GOP Senate candidate. In a victory speech Tuesday, Pappas cast his general election opponent as the president’s “handpicked candidate.”

“While New Hampshire families are struggling to make ends meet, John Sununu has thrown his lot in with Donald Trump,” Pappas told supporters.

Sununu has strongly criticized Mr. Trump in the past, and has broken with the president since earning his endorsement, pushing back on the Trump administration’s trade war with Canada. He has sought to keep the race’s focus on economic and cost-of-living issues, and portrayed Pappas as a “career politician” on Tuesday. 

“He’s not an independent voice for New Hampshire,” he said in a victory speech. “Chris Pappas has three main qualities: ineffective, partisan, and out of touch with New Hampshire.”