Trafalgar poll keeps Michigan Senate race close; our forecast stays at 70 percent

A Trafalgar Group survey of 1,079 likely voters in Michigan, fielded September 7-9, put Democrat Abdul El-Sayed at 46.3 percent and Republican Mike Rogers at 44.8 percent, with 0.2 percent for other candidates. The gap is 1.5 points. That is a close race, not a lead.

Our forecast did not change. Our model gives El-Sayed a 70 in 100 chance of winning the seat and Rogers 30 percent, the same split as our previous run earlier on September 10. The mean margin in our simulations moved from D+5.7 to D+5.9. The spread around that is wide: our 5th-to-95th percentile range runs from R+12.0 to D+23.8, which is to say our model does not rule out a clear win for either candidate.

The pattern is now familiar. Our estimate of the Michigan margin is several points more Democratic than the closest recent surveys, including this one, because the model weighs state polling against national conditions and its own priors rather than tracking the latest number. Our generic-ballot average stands at D+6.7 across 25 polls over the past 45 days. A 1.5-point result in a single Michigan survey is consistent with both that average and with a much tighter contest, which is why one more poll of this kind moves the forecast in tenths.

The seat is open, with Democrat Gary Peters the sitting senator and neither candidate an incumbent. Michigan matters to the arithmetic of Senate control, and that arithmetic remains near even: our model gives Democrats a 49 in 100 chance of a Senate majority and Republicans 50 percent, with a mean of 50.2 Democratic seats. Democrats need 51 seats for control and Republicans 50, because the vice president is a Republican and a 50-50 tie goes to their side.