Incumbent Senator Ed Markey’s dominant showing at the Massachusetts Democratic nominating convention on May 30, where he captured 73 percent of delegate support compared with 27 percent for challenger Representative Seth Moulton, has reinforced his position as the clear frontrunner ahead of the September 1 primary. Markey’s long tenure, established progressive record, and party endorsement provide structural advantages in a state where Democratic voters have historically favored continuity. Moulton’s more moderate profile and focus on generational turnover have yet to close the gap in early polling or delegate backing. Minor candidates Alexander Rikleen and Ayanna Pressley remain on the periphery with negligible support. A planned summer debate offers the main near-term opportunity for momentum shifts before primary voters decide.