John E. Sununu holds a commanding lead in the September 8, 2026, New Hampshire Republican Senate primary due to consistent polling advantages of roughly 30 points or more over Scott Brown in recent surveys, bolstered by Donald Trump’s February endorsement and extensive support from state legislators and party officials. Sununu’s prior Senate service, deep family ties in New Hampshire politics, and emphasis on local priorities have reinforced his frontrunner status among likely Republican voters, while Brown’s outsider profile and earlier primary bids have limited his gains. Dan Innis withdrew and endorsed Sununu, and Chris Sununu declined to run, further consolidating support. With the primary weeks away, only major late developments such as unforeseen scandals or health events could realistically narrow the gap reflected in current trader consensus.