Maine forecast narrows to 81 percent for Jackson after CNN poll

A CNN/SSRS survey of 880 likely voters in Maine, fielded August 31 to September 6, put Democrat Troy Jackson at 48 percent and Republican Susan Collins at 45 percent. The poll does not carry a margin of error in our payload, and a three-point gap on that sample is close enough that it is better read as a close race than as a measured lead.

Our model now gives Jackson an 81 in 100 chance of winning the seat, with Collins at 19 percent. That is down from 91 percent for Jackson in our previous run, earlier the same day. The expected margin moved with it, from D+8.4 to D+5.5, and the range of outcomes shifted: our 5th-to-95th percentile band now runs from R+4.7 to D+15.6, where before it ran from R+1.7 to D+18.7.

So the direction is a change, not a confirmation. Our recent numbers in Maine had been drifting toward Jackson through late August. The CNN/SSRS result is tighter than that drift implied, and the model has given back part of it. Jackson remains the favorite in our estimate, but the downside tail now includes a Collins win by four points or more.

Maine sits inside a Senate map our model still rates as more likely to go Republican. We give Democrats a 41 percent chance of Senate control and Republicans 58 percent, with a mean of 49.7 Democratic seats. Democrats need 51 seats for control; Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to them. On that arithmetic, a race with a 19 percent chance of going the other way is not a small part of the picture. Our national generic-ballot average stands at D+6.3 across 25 polls in the past 45 days.