Democrats at 93 in 100 for the House, 44% in the Senate as fall polling arrives

Fifty-eight days out, our model gives Democrats a 93 in 100 chance of winning a House majority, against 6% for Republicans, with a mean of 239.4 Democratic seats and 218 needed for control. One caveat belongs with that number: our simulation draws error nationally, by census division, by state and by district, but it does not include a term linking demographically similar districts in different places, because we have no cluster data for one. The House probability is therefore marginally firmer than a fuller decomposition would leave it. How much firmer is not measured in this run.

The Senate is closer to even and tilted the other way. Our model gives Democrats a 44% chance of winning control and Republicans 55%, on a mean of 49.9 Democratic seats. Democrats need 51 seats; Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to them.

Our generic ballot average stands at D+6.2, drawn from 24 polls over the past 45 days. The individual surveys still disagree on size. Morning Consult, fielding August 24-30 among 28,429 registered voters, had Democrats ahead 47.1% to 42.3%. An Economist/YouGov poll of 1,434 registered voters, fielded August 28-31, had it 46% to 40%, and a Reuters/Ipsos poll of 924 registered voters over the same dates had 43% to 38%. HarrisX for Harvard CAPS, fielded August 28-30, put Democrats at 51% to 49% among 2,100 registered voters and Republicans at 51% to 49% among its likely voter sample.

Iowa's Senate race accounts for the largest move toward Democrats in our forecast, up 12.5 points to a 35% chance for the Democrat, from 22%. An Emerson College poll for Nexstar, fielded August 31 to September 1 among 750 likely voters, had Republican Ashley Hinson at 49.5% and Democrat Josh Turek at 45.1%. Movement elsewhere in the Senate ran the other way: our estimate of the Democratic chance in South Carolina fell 10 points to 7%, New Hampshire fell 10 points to 81%, and Virginia fell 8.7 points to 90%. A Fabrizio, Lee & Associates poll for the National Republican Senatorial Committee, fielded August 27-30 among 600 New Hampshire likely voters, recorded Democrat Chris Pappas at 36%; the release carried no usable Republican share.

In the House, our estimate in Texas's 15th District fell 16.5 points, to a 36% Democratic chance from 52%. Our forecast in Ohio's 7th also moved toward the Republican, which we covered separately. Two new district polls show close races. Normington, Petts & Associates, polling likely voters August 27-31 for House Majority PAC, had Republican Carlos De La Cruz at 45% and Democrat Johnny Garcia at 44% in Texas's 35th District.