John E. Sununu maintains a commanding lead in the New Hampshire Republican Senate primary due to consistent polling advantages of roughly 35 points or more, bolstered by President Trump's February endorsement, extensive support from state Republican officials including the Senate president and executive councilors, and his prior service as a U.S. senator and House member from the state. Recent late-August polls from UNH and Saint Anselm reaffirm this margin ahead of the September 8 primary, while Scott Brown's campaign has focused on independence claims and criticism of Sununu's decision to skip additional debates in favor of grassroots outreach. Name recognition tied to the Sununu family political legacy in New Hampshire further reinforces the frontrunner position. A significant shift would require an unforeseen late development such as a major scandal or health event in the final days before voting.