A nifty catch by Philip Klein, eyeballing the latest data from Nate Silver’s model (as of 5:15 p.m. ET). Check it yourself. Democrats momentarily have an 18.4 percent chance of gaining two seats and winning a majority next month. Whereas Republicans have a 9.1 percent chance of gaining three, a 5.5 percent chance of gaining four, a 3.2 percent chance of gaining five, a 1.4 percent of gaining six, a 0.7 percent chance of gaining seven, and a 0.3 percent chance of shooting the lights out and gaining eight (which would leave them one seat shy of a filibuster-proof majority, for what it’s worth). Add those up and you get a 20.2 percent chance of 54 or better.

Which can be summed up in four words: Justice Amy Coney Barrett.

Klein on the path to 54:

Though Republicans were always favorites to keep the Senate, their odds have improved in recent weeks, with three states in particular giving them a boost. Republicans are now considered “likely” to keep their seats in Texas and Tennessee and North Dakota seems ready to flip into the Republican column. Barring any other major upsets, victories in those three races would be enough for Republicans to keep the Senate — hence their 81.6 percent chances overall.

To get to 54, the most likely scenario would be that Republicans win the tossup states of Nevada and Missouri, and then surge to victory in Arizona and Florida (two races that are currently tilting Democrat, but well within range of Republican victory). Beyond that, they’d have to start flipping some seats that are currently considered “likely” to remain Democrat, such as Montana and West Virginia.

Eh, I don’t know if Montana and Indiana, the latter of which he neglected to mention, are all that “likely” to remain Democratic. They’re leaning that way, with both Jon Tester and Joe Donnelly clinging to three-point leads. But Montana hasn’t been polled in three weeks and the latest from Indiana has Donnelly up four but with just 44 percent of the vote. In fact, in none of the four polls dating back to August has Donnelly topped 44, suggesting that a lot of Hoosiers are thinking hard about whether to stick with the incumbent. It’s likely that the GOP will be disappointed somewhere on Election Night — Missouri, Nevada, and Arizona are all leading candidates — but going for one for two on Montana and Indiana seems doable.

Whichever way they do it, if they can get to 54 then Collins and Murkowski might well be nonfactors during the next SCOTUS battle. Flake won’t be in the Senate at all, of course. Trump really might have the arsenal he needs to fill a Ginsburg or Breyer vacancy with a conservative.

That’s the good news. The not-so-good news, also from Silver’s model:

Click the link and add up the different probable outcomes and you’ll see that the GOP has about the same odds of holding the House as Democrats do of winning … at least 54 seats. They’ve got a 10 percent chance of winning at least 60. Gonna be a lot of subpoenas for Pat Cipollone to cope with next year.

There are no new swing-state polls as I write this but keep an eye on the one of Arizona that’s currently in progress (yes, in progress) at the NYT’s site, the Upshot. As I write this at a little after 5 p.m. on the east coast, they’ve compiled a sample of 299 people — not large enough yet to give us confidence in the topline numbers but large enough to make it worth paying attention to. Currently Martha McSally leads Kyrsten Sinema by four points, 49/45. If that holds through the end of the poll, it would be the second straight survey showing McSally ahead after trailing for most of the race. (The previous poll had her up six.) Stay tuned.