Massachusetts's deep Democratic lean and Ed Markey's decisive primary victory over Seth Moulton have solidified trader expectations for the November 3 general election. Consistent polling since summer shows the incumbent holding a 23-point or larger lead over Republican John Deaton, who faces the same structural headwinds that produced his 2024 loss to Elizabeth Warren. Deaton's self-funding and debate challenges have generated limited movement in surveys, while Markey's established record and party infrastructure reinforce the race's Solid Democratic rating from multiple forecasters. A late scandal, health event, or sharp national Republican surge could narrow the gap, yet current evidence points to barriers that keep the implied probability of an upset extremely low.