John E. Sununu maintains a commanding lead in the New Hampshire Republican Senate primary due to his established name recognition within the state's political landscape, prior service representing the state in Congress and the Senate, and a decisive endorsement from President Trump in February 2026. Recent polls from sources including the University of New Hampshire and Saint Anselm College show him consistently ahead of former Massachusetts Senator Scott Brown by margins exceeding 30 points among likely Republican primary voters, with other candidates such as Dan Innis withdrawing or endorsing Sununu. Brown's positioning as a relative newcomer, despite prior Senate experience, has failed to close the gap ahead of the September 8 primary. A major scandal, health issue, or unexpected shift in turnout could still alter the outcome, though current polling trends and campaign resources indicate limited pathways for challengers to overtake the frontrunner before voters decide.