Having taken time to examine all the competitive House and Senate races, the thing that most stuck out to me was both how broad the playing field is, but also how shallow.

Most prognosticators believe the GOP could pick up between 45 and 60 seats in the House. What is interesting, though, is that you are seeing very few non-open races where the GOP has already locked down the seat with a large lead in the polls. Instead of having 30 solid Republican pick-ups and 25 close races, there are few currently Democratic seats solidly in Republicans hands, but around 90 seats where there are decent indications of a seat possibly flipping. This mirrors what we have been seeing in the Senate, where, in the past week, at least one public poll in each of nine states has shown the race within the margin of error.

There are deep blue districts like Barney Frank’s that are surprisingly close, but at the same time you have freshman Democrats in deep red districts, like Frank Kratovil, who should be losing badly in a wave election year, and yet their races remain very close.

Going district by district, you could make the case that Republicans on a good night could net 70 seats by narrowly winning many swing districts where the polling is close and the GOP candidate seems to be gaining. By the same token, though, there is a reasonable district-by-district argument for how Democrats could keep the majority with many narrow wins, especially if their GOTV operation can close some of the projected partisan turnout gap.

The broad width but shallow depth of the playing field this year has put the fate of a huge number of districts up in the air. While there is no doubt the GOP will make big gains on election night, the plausible range of pickups is incredibly wide. Depending on if the national mood breaks one way or another, dozens of seats could be won or lost by very narrow margins.