The nationwide generic ballot tells us almost nothing about which party is likely to win control of the House. If you really want to get a handle on how tomorrow’s elections will turn out, you need to go through all the competitive districts, one by one.
If you do that, you find the balance of power in the House of Representatives is really close — probably within a handful of seats.
Let’s begin with Ballotpedia’s big list of competitive districts. Better to begin by looking at too many districts than too few — and they selected 80 seats.
That’s 71 Republican-held seats and 9 Democratic ones. Why do the Republicans have so few districts where they could win a Democrat-held seat? Because with a few exceptions, they already picked all the low-hanging fruit in 2010 and 2014, and held on to it through 2016. There just aren’t that many competitive districts represented by Democrats left. …
… Outside of Pennsylvania, it looks like Democrats will pick up 22 seats, just short of the 23 they need. But Stauber’s win in Minnesota flips one seat back to the GOP, giving Democrats a net gain of 21. If Pennsylvania kept the status quo, the Republicans would enjoy a 220–215 majority.
With Pennsylvania’s new lines, the consensus is that the state’s congressional balance will shift from 13–5 Republican (at the beginning of this Congress) to 9–9. This gives Democrats four additional seats, adding up to a net change of 25 seats — just past the 23 seats they need for a majority.
Under this scenario, the good news for Democrats is that they win the House, gain the chairmanships of the House committees, and can investigate the Trump administration to their hearts’ content. The bad news is that getting much of anything passed with just 220 Democrats will be extremely difficult.