Michael Minogue's commanding lead in the Massachusetts Republican gubernatorial primary stems primarily from his April 2026 convention victory, where he secured 70% of delegate support and the party endorsement, far ahead of Brian Shortsleeve. His substantial self-funding from the sale of his medical device company has created a decisive cash advantage, enabling heavy advertising and a focus on the general election matchup against incumbent Democrat Maura Healey. Mike Kennealy, who received about 14% at the convention, withdrew and endorsed Minogue, further consolidating support among Republican primary voters and convention attendees. With the September 1 primary just days away, trader consensus reflects this structural edge, though low-probability scenarios such as unexpectedly high Shortsleeve turnout in the final days or major late-breaking developments could still alter the outcome.