With less than a week left to go until Election Day, the odds of the Democrats controlling 50 seats or more in the Senate are as high as they’ve been: 72 percent. That’s still far from a sure thing, but the trendline looks very good. There’s one other first that we’re seeing: for the first time, the median number of Democrat-held seats is now 51, not 50.
Fifty-one seats has two advantages. One, it gives the Democrats a bit of a cushion going into 2018, a midterm election where they’re defending a number of red-state seats that they won in 2012. And two, it keeps the Democrats from having to depend on their least-liberal member to reach 50 on non-cloture votes, so it keeps Joe Manchin from being perpetually in the driver’s seat. (Of course, any 5-seat gain includes Evan Bayh, so that would still leave Evan Bayh in the driver’s seat.)
The main reason that we’re seeing our Senate odds increase is the race in Pennsylvania, where Katie McGinty now has an 89 percent chance of winning, based on a polling average of 45-41. Her race with Pat Toomey has been very back-and-forth all year, but she’s led the last eight polls; she hasn’t trailed since an Emerson poll from mid-October, and a Franklin & Marshall poll from a few days ago giving her a 12-point lead is the coup de grâce.
If you’ve been following our Senate model closely, you’ve probably seen the pattern where there are three races (Illinois, Indiana, and Wisconsin) that were all pretty solid in the Democrats’ corner, and then three more races (Nevada, New Hampshire, and Pennsylvania) hanging around in the “tossup” realm. However, what’s surprising here is that Pennsylvania is now tied for the second-likeliest Democrat pickup, as Wisconsin and Indiana have both become more competitive in the last few weeks. (In fact, just in the last few days we’ve seen a Marquette poll of Wisconsin giving Russ Feingold only a 1-point lead, and a Monmouth poll of Indiana finding Evan Bayh in a tie. Those have pushed Wisconsin down to 89 percent odds, and Indiana down to 79 percent odds.)