John E. Sununu maintains a commanding lead in the New Hampshire Republican Senate primary, set for September 8, 2026, due to his deep state roots as a former U.S. senator and member of a prominent political family, combined with consistent polling advantages of 35 points or more over Scott Brown. Recent surveys from the University of New Hampshire and Saint Anselm College show Sununu at 54-60% support among likely Republican primary voters, bolstered by endorsements from state legislators, executive councilors, and groups like the State Employees' Association. Brown, a former Massachusetts senator and ambassador, has struggled to close the gap despite multiple debates and joint appearances. Minor candidates including Dan Innis register negligible support. The primary's proximity and Sununu's established voter base in a low-turnout contest limit realistic paths for an upset, though an unforeseen late development such as a major scandal or health issue could theoretically alter dynamics before ballots close.