Former Republican Senator John E. Sununu has won his party's Senate nomination in New Hampshire, defeating fellow former senator Scott Brown in a contest with significant implications for control of the US Senate in the midterm elections. The seat, currently held by retiring Democrat Jeanne Shaheen, is regarded as a top Republican target despite the party not having won a Senate race in the state for 16 years, making the outcome of the wider general election closely watched.

Sununu, whose father and brother both served as New Hampshire governor, secured endorsements from President Donald Trump, Senate Majority Leader John Thune and the National Republican Senatorial Committee, despite past criticism of Trump. Brown, a former Trump ambassador, accused Sununu of being "beholden" to the party establishment, while Sununu insisted his focus was solely on New Hampshire and distanced himself from needing Trump's campaign support. He will face either Congressman Chris Pappas or Karishma Manzur, who are contesting the Democratic nomination, in the general election, with Sununu citing affordability and cost-of-living issues as his key priorities amid a challenging political climate for Republicans.