Abacus poll puts Turek up nine in Iowa, and our forecast flips to lean Democratic

An Abacus Data survey of 2,500 likely voters, fielded August 29, has Democrat Josh Turek at 54 percent and Republican Ashley Hinson at 45 percent in Iowa's open Senate race.

That is the largest lead either candidate has held in the polling our model has taken in for this race, and it moved the forecast. Our model now gives Turek a 65 in 100 chance of winning the seat, up from 27 percent in the run completed earlier the same evening. The mean projected margin shifted from R+3.9 to D+2.4. Our 5th-to-95th percentile range runs from R+8.1 to D+13.1, so outcomes on either side remain well inside what the model considers ordinary.

This is a change rather than a confirmation. Our previous piece on this race, published earlier today, described a forecast nudged upward on polling that had the two candidates within two points. A single 2,500-person sample showing a nine-point Democratic lead is a larger input than the model had been working with, and it carried the estimate across the even-odds line. Neither candidate is an incumbent; the seat is currently held by Republican Joni Ernst.

One poll is one poll, and a forecast that moves 38 points on a single survey is a forecast that can move back on the next one. The wider picture behind the Iowa number is a national environment our average puts at D+6.7 on the generic ballot, across 22 polls in a 45-day window.

For Senate control, our model gives Democrats a 51 percent chance and Republicans 49 percent, with a mean of 50.3 Democratic seats. Democrats need 51 seats for a majority and Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to the Republicans. Iowa is one of the seats that decides which side of that line the chamber lands on.