All things considered, the Republicans remain favored to pick up the six seats they need for a majority. That’s what the polls are indicating, and so are the most of the mathematical forecasting models, which extrapolate from survey data. At this stage, however, it is perfectly possible that neither side will emerge from next Tuesday with victory sealed. Runoffs are likely in Georgia and Louisiana. We could have to wait until early January to find out who controls the upper chamber.
Enten examines the Georgia Senate race, which he estimates has a 70 percent chance of going to a runoff:
We don’t have much polling evidence on which candidate might have the advantage in January. Besides how the campaign might evolve, we don’t really know who will vote in a runoff. No pollster, even those who have asked about the runoff, have tried to model the electorate in January. As I noted last week, there’s no really good precedent for a January runoff in a midterm election.
Alex Rodgers, on the other hand, figures that a Georgia runoff favors Republicans:
Republicans have won the past five statewide runoff contests by doing a better job turning out their base in the conservative-leaning state. In 2008—the last Senate runoff in the state—Republican Saxby Chambliss won the first ballot by three percent of the vote, and then a month later trounced his Democratic opponent Jim Martin in the runoff by 15 points. Republicans were boosted in part by the lower turnout, which was around 57 percent of the number of voters who cast ballots in the same Senate race a month earlier.
Aaron Blake imagines how these races will play out if they determine control of the Senate:
If that’s the case, these two states will be inundated with money from all over the country, and nobody will be able to escape the importance of their state’s runoff. And conversely, if the Senate majority isn’t at stake, these could turn into pretty sleepy contests.