Model moves Alaska Senate toward Peltola in a single overnight run

Our model now gives Democrat Mary Peltola a 34 in 100 chance of winning the Alaska Senate race against Republican incumbent Dan Sullivan. That is up 10.8 points from the 23 percent estimate in our previous run, dated August 16 at 10:15 PM ET. The two runs are one day apart.

The expected margin narrowed alongside the probability. Our model now puts the mean margin at R+2.8, against R+4.9 in the earlier run, and its 5th-to-95th percentile range at R+13.8 to D+8.3, compared with R+15.7 to D+6.2 before. Both runs describe a race our model treats as competitive but tilted to the Republican.

The polling in the payload predates the earlier run. Data for Progress surveyed 605 likely voters in Alaska from July 28 to August 4 and published two sets of numbers from that field period: Sullivan 41 percent to Peltola 47 percent in one, and Sullivan 47 percent to Peltola 53 percent in the other. No margin of error is given for either. Nothing in the payload records a survey arriving between the two model runs, so we cannot attribute the shift to new data. The model moved; the cause is not established here, and we are not going to guess at one.

Alaska sits inside a chamber our model rates close to even. Nationally, we give Democrats a 47 percent chance of winning Senate control and Republicans 53 percent, with a mean of 50.1 Democratic seats. Democrats need 51 seats for a majority and Republicans 50, because the vice president is a Republican and a 50-50 tie goes to the Republicans. Our national generic-ballot average stands at D+6.7 across 26 polls from the past 45 days. Election day is November 3, 78 days out.