Two Kansas polls show a close race; our model still favors Marshall

Two new surveys of the Kansas Senate race put Republican Roger Marshall and Democrat Adam Hamilton within a few points of each other. Public Policy Polling, on a survey of registered voters fielded August 7-8 and sponsored by Senate Majority PAC, had Marshall at 46 percent and Hamilton at 45. GBAO, polling 600 likely voters July 8-13, had Marshall at 47 percent and Hamilton at 43. Neither poll's margin of error is available to us, so both are best read as close races rather than as measured leads.

Our model now gives Hamilton a 14 in 100 chance of winning the seat and Marshall an 86 percent chance. The previous run, from earlier this afternoon, had Hamilton at 5 percent. The projected margin barely moved: R+11.9 now against R+10.4 before. What changed is the width of the distribution. Our 5th-to-95th percentile range runs from R+30.3 to D+6.3, against R+20.9 to D+0.2 in the prior run.

That combination is the story. Polls this close to even are hard to square with a double-digit projected margin, and our model has responded mostly by admitting more uncertainty rather than by moving its central estimate. Kansas is still a race it expects Marshall to win, with a Democratic path that is no longer close to negligible.

Nationally, our average of 28 generic-ballot polls over the past 45 days stands at D+6.5. In the Senate, we give Democrats a 49 percent chance of winning control and Republicans 50 percent, with a mean of 50.2 Democratic seats; Democrats need 51 seats and Republicans 50, because a 50-50 tie goes to the Republicans under a Republican vice president. In the House, we put the Democratic chance of a majority at 93 percent, with a mean of 240.1 seats against the 218 needed. One caveat is ours: our simulation correlates district error nationally, by census division and by state, but we have no cluster data to link demographically similar districts across the map, so that House figure is marginally firmer than it should be.