Global Strategy Group poll finds a close Iowa Senate race, and our estimate holds

A Global Strategy Group survey of 800 likely voters in Iowa, fielded August 27-31, puts Democrat Josh Turek at 46 percent and Republican Ashley Hinson at 42 percent, with 6 percent for other candidates. No margin of error is reported in what we have, so we treat the four-point gap as a close race rather than a measured lead.

The poll did not change our estimate in any meaningful way. Our model gives Turek a 31 in 100 chance of winning the seat, against 69 percent for Hinson. The previous run, from earlier the same morning, had Turek at 32 percent. Our mean margin is unchanged at R+3.0, and so is our range: the model's 5th-to-95th percentile interval runs from R+13.1 to D+7.2, which spans outcomes on both sides by comfortable margins.

That stability is worth stating plainly, because this race has not been stable. Our published estimate has moved sharply in both directions over the past two weeks. The new numbers sit closer to the Democratic end of the polling we have averaged, but they arrive alongside enough other data that the average absorbed them rather than being redirected by them. Iowa is an open seat; Republican Joni Ernst is the incumbent and neither candidate on our ballot holds the office.

Nationally, our model gives Democrats a 41 percent chance of Senate control and Republicans 58 percent. Democrats need 51 seats for a majority; Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to their side. Iowa is one of the seats that determines which side of that threshold the chamber lands on, and at a mean of 49.8 Democratic seats our simulations sit just below it. Our generic-ballot average is D+6.1 across 24 polls in a 45-day window.