Senate sits at even odds as our House estimate holds at 95 in 100

Our generic ballot average stands at D+6.7, drawn from 24 polls fielded in the last 45 days, as of 6:32 AM ET on September 12. Fifty-two days remain before the November 3 election.

The Senate is even. Our model gives Democrats a 50 in 100 chance of winning control and Republicans the same, with a mean of 50.3 Democratic seats. The seat thresholds are not symmetric: Democrats need 51 for a majority and Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to the Republicans.

In the House, our model puts the Democratic chance of a majority at 95 percent, with a mean of 240.7 seats against the 218 needed. One caveat belongs with that figure. Our simulation draws error at four correlated levels — national, census division, state, and each district on its own — but it has no term correlating demographically similar districts in different places, because we have no cluster data for one. That missing layer leaves our House control probability marginally firmer than a fuller decomposition would. We cannot quantify the gap for this run.

Maine produced the largest movement on our board, with the Democratic win probability there falling 25.2 points, from 89 percent to 64 percent. Ohio moved 20.5 points the other way, from 45 percent to 66 percent, after an InsiderAdvantage survey of 1,200 likely voters, fielded September 8-9, put Sherrod Brown at 47.3 percent and Jon Husted at 41.9. Our Iowa estimate rose 11.6 points to 47 percent alongside three YouGov samples fielded September 3-8: Josh Turek at 45 percent to Ashley Hinson's 43 among 2,127 likely voters, 47-43 among a separate 2,041 likely voters, and 44-43 among 2,166 registered voters. South Carolina rose 9.4 points to 17 percent, North Carolina 7.1 points to 85 percent, and Kansas 4.5 points to 10 percent.

Several of the day's other surveys were close. InsiderAdvantage polled 1,200 likely voters in Texas on September 8-9 and found James Talarico at 47.1 percent and Ken Paxton at 45.6, and 1,200 likely voters in South Carolina over the same dates, with the Republican at 45.1 percent and Democrat Annie Andrews at 43.2. The Trafalgar Group surveyed 1,079 Michigan likely voters September 7-9, with Abdul El-Sayed at 46.3 percent and Mike Rogers at 44.8. Public Policy Polling surveyed 629 South Dakota registered voters September 8-9, putting Republican Mike Rounds at 45 percent and independent Brian Bengs at 42. In Florida, a Change Research poll of 1,107 likely voters for Freedom Project USA, fielded September 7-9, had Ashley Moody and the Democrat tied at 47 percent apiece; a Quantus Insights survey of 733 likely voters, fielded September 8-10, had Moody at 50.4 percent to 43.