Republicans Need A Systematic Polling Error To Win The House
538
As I wrote earlier this week, Democrats almost certainly need a systematic polling error to win the Senate. By that I mean: They need for the polls to be off everywhere, or at least in certain key clusters of states, to win the Senate. A polling error in just one or two races (say, Beto ORourke wins in Texas) probably wouldnt be enough: Democrats are defending too much territory and have too many problems elsewhere on the map just to get lucky.
That conclusion about the Senate ought to be fairly intuitive, I think. Even if you credit Democrats with wins in all the toss-up races, that wouldnt be enough it would only get them to 50 seats. What might be more surprising is that the same conclusion holds for Republicans in the House. They need for there to be a systematic polling error too. If the polls are about right overall but Republicans are hoping to getting lucky in the swing districts, it probably wont happen the odds are stacked heavily against them.
The reason its counterintuitive is because you cant really identify 23 districts that are safe bets to flip to Democrats (thats the number they need to take the House). In the Deluxe version of our model (the one Ill be focusing on here), only 193 seats are considered to be solid Democratic (at least a 95 percent chance of a Democratic victory). If Democrats won only those seats and no others, theyd actually lose two seats from the 195 they control now. Another 15 seats are likely Democratic, where Democrats have at least a 75 chance of winning. Win those as well, and Democrats are
still up to a net gain of only 13 seats.
The model then has 34 seats in its three most competitive categories: lean Democratic (eight seats), toss-up (16 seats) and lean Republican (10 seats). If Republicans win 24 of those 34 seats assuming everything else goes to form theyll keep the House.