Trafalgar finds Iowa Senate race close, and our estimate holds at 42 in 100

A Trafalgar Group survey of 1,089 likely voters in Iowa, fielded September 16-18, puts Republican Ashley Hinson at 44.0 percent and Democrat Josh Turek at 42.1 percent, with 3.4 percent for other candidates. The gap is under two points, which is another way of saying the poll found a close race rather than a lead for either candidate.

Our forecast did not move. The model gives Turek a 42 in 100 chance of winning the open Iowa seat and Hinson 58 percent, the same split as our previous run at 8:32 AM ET on September 19. The mean margin stays at R+1.1, and the 5th-to-95th percentile range still spans R+10.8 to D+8.6 — wide enough that outcomes on either side of a narrow result remain well within our distribution. The new number sits close to that mean, so it confirms rather than changes what was already in the average.

Iowa matters to the chamber arithmetic. Our model gives Democrats a 52 percent chance of Senate control and Republicans 48 percent, with a mean of 50.5 Democratic seats. Democrats need 51 seats; Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to the Republicans. A race our average scores at roughly even is the kind that decides which side of that line the chamber lands on.

The House picture is steadier. Our average of 28 generic ballot polls over the past 45 days stands at D+7.3, and the model gives Democrats a 97 percent chance of reaching the 218 seats needed for House control, with a mean of 242.7 seats. One caveat is ours to own: our simulation correlates error nationally, by census division, by state and by district, but not across demographically similar districts in different places, because we lack the cluster data for it. That makes the House control number slightly firmer than a fuller error model would leave it.