Our Kansas Senate odds move to 25 in 100 for Hamilton after an Emerson poll

Our model now gives Democrat Adam Hamilton a 25 in 100 chance of winning the Kansas Senate race, up from 5% in our run of September 11 at 10:02 AM ET. That is a gain of 20.7 points of win probability over seven days. Republican incumbent Roger Marshall is at 75%.

The margin estimate moved with it. Our mean margin is now R+4.0, against R+10.3 a week ago. The spread of simulated outcomes shifted and widened at the Democratic end: our 5th-to-95th percentile range runs from R+13.7 to D+5.8, where last week it ran from R+20.3 to R+0.3.

One survey arrived in between. An Emerson College poll for The Hill, fielded September 15-16 among 750 likely voters, put Hamilton at 44.8% and Marshall at 43.3%, with 3.7% for others. That gap is small enough that the poll is best read as a close race rather than as a lead for either candidate. It is also a different picture from the co/efficient survey of 915 likely voters fielded September 8-10, which had Marshall at 49% and Hamilton at 44%. The Emerson numbers are the newer of the two and the only ones added since the previous run, so most of this week's movement traces to them, though our estimate also responds to national conditions and to the passage of time.

Our national generic-ballot average stands at D+7.4, drawn from 28 polls over the past 45 days. In the Senate as a whole, our model gives Democrats a 52% chance of a majority and Republicans 47%, with a mean of 50.5 Democratic seats; Democrats need 51 seats for control, Republicans 50, because the vice president is a Republican and a 50-50 tie goes to them. Kansas is one of the seats that decides which side of that line the chamber lands on.