Times/Siena poll finds Kansas Senate race even, and our Hamilton odds rise to 35 percent

A New York Times/Siena University survey of 605 likely voters, fielded September 22-30, finds the Kansas Senate race between Republican Sen. Roger Marshall and Democrat Adam Hamilton effectively even. In the head-to-head version of the question, Marshall has 46.67 percent and Hamilton 46.39 percent. In a version that also offers other candidates, Hamilton has 44.87 percent, Marshall 44.76 percent, and 4.86 percent choose someone else. Neither gap is meaningful. The race is close.

Our model moved after this survey was added. It now gives Hamilton a 35 in 100 chance of winning the seat, up from 18% in our previous run earlier this morning. Marshall's chance falls to 65% from 82%. Our projected margin narrows to R+2.1 from R+5.1.

That is a change from what we reported on October 2, when two earlier polls left our Hamilton odds roughly where they were. This survey moved them.

The range of outcomes remains wide. Our model's 5th-to-95th percentile range now runs from R+11.2 to D+7.0, compared with R+14.2 to D+4.0 before. Marshall is still the favorite in our estimate, but the band now extends further toward a Hamilton win.

Kansas matters for the chamber as a whole. Our model gives Democrats a 55% chance of winning Senate control and projects them at an average of 50.7 seats. They need 51 seats for control. Republicans need 50, because the vice president is a Republican and a 50-50 tie goes to them.