We’re Back From The Future. Which Of These Wildly Different Midterm Outcomes Would You Believe?

Welcome to FiveThirtyEight’s weekly politics chat. The transcript below has been lightly edited.

natesilver (Nate Silver, editor in chief): Today I’m coming to you from the future. Or maybe I’m not. The rest of you will have to figure out whether I’m really coming from the future or just pulling your leg. But for now, I’ve timeported myself back from Nov. 7, and I’m going to tell you what happened on Election Day. Tell me whether you believe me or not.

nrakich (Nathaniel Rakich, elections analyst): There’s approximately a 0 in 1 chance that Nate is coming to us from the future.

natesilver: Here’s what happened: Democrats picked up only 16 House seats, short of the 23 they needed to take control of the House. They might win another one or two once California finishes counting its returns, but they’re not going to get to 23.

And in the Senate — oh, boy.

Democratic incumbents lost in North Dakota, Missouri and Indiana. And they didn’t gain any Republican seats, although there’s a chance that Kyrsten Sinema could win Arizona if it goes to a recount (don’t get your hopes up, Democrats — she’d need almost everything to go right). So it looks like we’ll end up with a 54-46 Republican-controlled Senate.

There were a few bright spots for Democrats. Andrew Gillum won the Florida gubernatorial election. Republican Gov. Scott Walker lost by 2 points in Wisconsin. But overall, Republicans beat their polls by an average of 2 to 3 points — a lot like 2016, to be honest.

Democratic turnout was high. But GOP turnout was high too, and the election was fought in very red places.

OK, so that’s what happened.

Why don’t you guys ask me some questions so that you can verify I’m telling the truth?

julia_azari (Julia Azari, political science professor at Marquette University and FiveThirtyEight contributor): I’m not sure what kinds of questions. I think I don’t understand the rules of this game.

But this scenario seems plausible to me.

What was wrong with the polls in Arizona?

natesilver: Not sure you could say much was wrong with them — Sinema was up only 2 points in our forecast, and she’s down by 0.3 points based on votes counted so far.

That’s the thing — the polls weren’t really that far off. Just almost all of them were off in the same direction.

nrakich: That scenario is unlikely in the House, but it’s believable in the Senate. A Democratic gain of 16 House seats falls outside the 80-percent interval of the most likely possible outcomes in our model. That would mean Democrats basically just won the seats that are clearly in their favor right now — e.g., the Iowa 1st, the Virginia 10th, a handful in Pennsylvania — but not much else.

There’s about a 20 percent chance that Republicans pick up three or more seats in the Senate. Joe Donnelly of Indiana and Claire McCaskill of Missouri would probably be two of the first Democratic incumbents to fall in that scenario.

natesilver: I think pollsters are still sorting it out, but there’s a sense that wavering Republican voters came home to Trump at the end. We’re in an era where everything is very polarized along presidential lines, and that little uptick in Trump’s approval rating at the end may have helped, even though we were dismissive about it beforehand.

julia_azari: This is my sense about 2016 and politics in general: Predictability is making things, weirdly, slightly harder to predict.

sarahf (Sarah Frostenson, politics editor): I think there’s something fishy in Future Nate’s count of House seats that Democrats picked up.

What can you tell us about those House seats?

natesilver: They didn’t necessarily fit any one pattern. GOP incumbents were a bit stronger than expected in some places. And Democrats were disappointed with the results in Texas and Florida, where they didn’t get much of a Hispanic turnout. There were some impressive Democratic victories — Richard Ojeda somehow won in the West Virginia 3rd, for example, which just doesn’t make a ton of sense given how the rest of the night went, but that’s what happened. There just weren’t enough of them.

nrakich: Here’s a question for you, Nate: What was Trump’s approval rating on Election Day?

natesilver: The national exit poll had it at 45 percent.

But, again — Democrats actually had a fairly good night, in some ways! They won the popular vote for the House by 6 points. They just lost nine battleground races by 2 percentage points or less.

julia_azari: What were the implications of this for the “shy Trump voter” phenomenon? Does this result debunk it, since it happened when Trump wasn’t actually on the ballot? Is the problem with the sampling or the likely voter screen? Or just unavoidable error? I want to know what this means for the nationalization of politics.

Also, were there any purple states where voters split the ticket on governor and Senate races?

natesilver: Sure. Ohio split, for example.

Plus some of the obvious ones, like Massachusetts and Maryland.

julia_azari: Right, Massachusetts is weird.

nrakich: Hey.

julia_azari: Did any of the top-shelf competitive races split? Did Sen. Tammy Baldwin win?

natesilver: Of course Baldwin won — it was always a Republican pipe dream to beat her.

julia_azari: I’ve seen a lot of yard signs for Leah Vukmir, her Republican opponent … (Please note that I am trolling Nate and this is not a factual statement.)

What about Bill Nelson? Democrats held on to his Florida Senate seat?

And wait … none of the competitive states that had both a governor and Senate race split? Just blue states with popular red governors?

natesilver: Yeah, Nelson held on.

And yet again, yard signs weren’t that predictive. But to your earlier question, Julia — there is some question about a “shy Trump” effect. The random digit dial polls tended to show better results for Democrats than the list-based sampling polls, and they may have been more affected by Democrats’ superior enthusiasm.

nrakich: So both Nelson and Gillum won in Florida, but Democrats were disappointed with low Hispanic turnout?

The thing about Florida is that it’s a state where Hispanic voters might help Republicans. Those southern Florida districts are heavily Cuban-American, a GOP-leaning group.

But honestly, that’s the only thing that seems inconsistent to me about your narrative. I buy that you’re from the future.

natesilver: Nathaniel, I think you’re neglecting that Nelson and Gillum both went into the election up several points. They were up by 4 points and 6 points, respectively, in our final polling average, and they each won by about 2 points.

nrakich: But why would Democrats be disappointed? They still won.

natesilver: Because they lost almost all the toss-up House races there, other than the Florida 27th (which maybe shouldn’t have been thought of as a toss-up to begin with). In the 26th, Republican Carlos Curbelo hung on — by 9 points, in fact.

julia_azari: So what we’re doing here is looking at a lot of small shifts in our expectations — no major upsets?

natesilver: What we’re doing here is that I’m coming back from the future and telling you what happened.

In the House, we had nine candidates (seven Republicans and two Democrats) win in races where they had less than a 20 percent chance of doing so. So there were some surprises there. Not as much in the Senate, really.

nrakich: Who was the other Democrat (other than Ojeda)?

natesilver: Ammar Campa-Najjar, of all people — bad night for Duncan Hunter in the California 50th.

Although, I should note that technically it’s still possible for Hunter to win — it’s just that the late mail ballots are expected to be Democratic.

sarahf: And what can you tell us about the seven Republicans? Any trends there?

natesilver: Yeah, there were several races where the Republicans were only slightly behind in the polls, but our model was very bullish on Democrats based on their fundraising.

The fundraising was a good sign of Democratic enthusiasm. But Republicans were enthusiastic too, even though they didn’t donate much money. Big-time donations from donors like Sheldon Adelson helped a lot. Republican efforts to triage basically worked.

nrakich: A lot of the fundraising was inefficiently distributed (*cough* Beto *cough*), so I certainly believe that the fundraising could fall flat.

julia_azari: I find how seemingly mundane the surprise is compelling, but my objection on the Senate side is that if things go badly for the Democrats, there will be at least one more incumbent loss — in Florida, or in Montana, or a true upset in Wisconsin, where underpolling of rural voters may be a real thing.

natesilver: Jon Tester won by 9 points in Montana. That was sort of a surprise in the opposite direction.

nrakich: Small state, popular incumbent. That checks out.

natesilver: But wait. Something’s happening. Something strange.

I have to go back into the timeporter.

[several hours pass]

julia_azari: I call BS on multi-directional surprises.

natesilver: Well, folks. I just got back from the future. It turns out that Democrats had a really, really good night. They’re going to win somewhere between 53 and 55 House seats, depending on a couple of California districts. And they somehow won the Senate, thanks to Texas! I guess Beto O’Rourke is going to be our next president now.

You guys should probably ask me a few questions about what happened, since it’s not too often you get to talk to someone from the future.

nrakich: Did Heidi Heitkamp win in North Dakota, or did Democrats have to make up for that loss elsewhere?

natesilver: She lost by 8.

But Beto O’Rourke won, and Democrats won all the toss-ups.

julia_azari: Where else did the Democrats pick up in the Senate?

What was the national House popular vote?

natesilver: Democrats won Arizona by 7 (!) and Nevada by 5 (!). Pollsters really underestimated Democratic performance in the Southwest.

The Democrats made huge gains in California, and it’s not out of the question that Republican Rep. Devin Nunes could lose once all the mail ballots are counted (although I wouldn’t bet on it).

nrakich: Eh, I don’t know about that. I’d say Democrats’ best path to a Senate majority lies with the incumbent in an underpolled, small state winning, not with a pro-impeachment Democrat who’s trailing in about a bazillion polls defeating Ted Cruz.

natesilver: But, Nathaniel, the polls weren’t that great.

For some reason, people don’t blame the polls unless Republicans beat their polls.

Democrats are going to win the popular vote for the House by something like 11 or 12 points, though.

sarahf: Was turnout lower among Republicans, too?

natesilver: It’s not that turnout was lower among Republicans. It’s just that all cylinders were firing for Democrats: There was very high turnout among suburban women and baby boomers and relatively high turnout among black/Hispanic/Asian voters. And independent voters went Democratic in the House by 14 points in the national exit poll.

julia_azari: To go back to an earlier question, what was Trump’s approval rating on Election Day?

natesilver: 44 percent.

But the small fraction of voters who had no opinion of Trump overwhelmingly backed Democrats.

nrakich: I’d bet more money on the polls in North Dakota being off than the polls in Texas. We have multiple high-quality pollsters in Texas. In North Dakota, it’s Fox News (a very good pollster) and then a handful of outlets without long track records of success.

natesilver: You can bet as much money as you want — but I’m from the future, and I know what happened.

Pollsters were baking in too many assumptions about a 2010- or 2014-type turnout — if they’d relied on self-reported voting intention, they would have come a lot closer to predicting the Democratic surge.

nrakich: That’s a narrative I would believe if Nate’s scenario came to pass.

julia_azari: What happened in the governors races?

natesilver: Democrats won all the highly competitive races, except in Kansas and Alaska.

Scott Walker actually almost held on in Wisconsin, losing by just 1 point, but a loss is still a loss.

nrakich: So Walker did better in your “Democratic surge” scenario than your “revenge of the Republicans” scenario?