CONCORD, N.H. — Former Republican Sen. John E. Sununu and Democratic Rep. Chris Pappas won their parties’ U.S. Senate primaries on Tuesday, Sept. 8, 2026, setting up a high-stakes November matchup for the open seat held by retiring Democratic Sen. Jeanne Shaheen, CBS News and other outlets projected.

Sununu, 61, defeated former Massachusetts Sen. Scott Brown in the GOP primary. He previously represented New Hampshire in the House and Senate before losing to Shaheen; he is the son of former Gov. John H. Sununu and brother of former Gov. Chris Sununu. Pappas, 46, a House member since 2019 and a member of the bipartisan Problem Solvers Caucus, defeated progressive challenger and medical scientist Karishma Manzur despite a cycle that has seen several progressive primary wins elsewhere, CBS reported.

Shaheen endorsed Pappas as her preferred successor. New Hampshire has not elected a Republican senator since 2010 and has not backed a Republican presidential nominee since 2000, even as Republicans have held the governor’s office since 2017. Pappas has called the general election “highly competitive,” telling CNN it “will continue to be tight until the very end,” per CBS.

With Republicans holding 53 Senate seats, Democrats would need to net four flips to retake the chamber while defending open and contested seats such as New Hampshire. Separately on Tuesday, Trump-backed auto executive Anthony DiLorenzo won the GOP primary for Pappas’s open House seat, according to The Hill and the New York Times.

An open Senate map concentrates power in a handful of swing states. Granite State voters just narrowed the field; November decides whether Shaheen’s seat stays blue or flips.

Sources