Co/efficient poll finds a close Maine Senate race; Jackson's chance edges to 60 percent

A new co/efficient survey of 1,240 likely voters in Maine, fielded September 28-30, puts Republican Sen. Susan Collins at 48 percent and Democrat Troy Jackson at 46 percent. A two-point gap in a single poll is a close race, not a lead.

Our model now gives Jackson a 60 in 100 chance of winning the seat, down from 62% in the run earlier this afternoon. Collins's chance rises to 40% from 38%. The poll nudged the forecast rather than changed it.

The model's average margin moved from D+1.7 to D+1.4. Its range of plausible outcomes remains wide: the 5th to 95th percentile now runs from R+7.9 to D+10.6, compared with R+7.5 to D+10.9 before. Both ends of that range sit well outside the gap between the two candidates in our average, which is why a small shift in the margin produces only a small shift in the probability.

Maine matters to the national picture. Our model gives Democrats a 53% chance of winning Senate control and Republicans 46%, with Democrats averaging 50.6 seats in our simulations. Democrats need 51 seats for control and Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to the Republicans.