The Washington Post published a story late Thursday that started a heated argument in the FiveThirtyEight offices. So we’re doing an extra 2016 Slack chat this week! The transcript below has been lightly edited.

micah (Micah Cohen, politics editor): It comes up every presidential primary, and it’s always simultaneously fun and eye-roll-inducing when it does: the contested convention. The dream of all political obsessives, a contested convention occurs when no candidate enters with the required number of delegates to clinch the nomination. On Thursday evening, Robert Costa of The Washington Post reported that GOP bigwigs are “preparing for the possibility of a brokered convention as businessman Donald Trump continues to sit atop the polls in the GOP presidential race.” The basic plan: If the Republican establishment can’t stop Trump in primaries and caucuses, they’ll have to do it at the convention.

So, is a contested convention really possible?

clare.malone (Clare Malone, senior political writer): Anything is possible, Micah.

harry (Harry Enten, senior political writer): What is the definition of “really possible”? It’s really possible that Nate, Clare and I go to Vegas and play poker tonight, but chances are that it won’t happen.

clare.malone: I have no plans.

natesilver (Nate Silver, editor in chief): Plenty of flights still available. We could make it.

micah: Let me reframe: How likely do you think a contested convention is? And what would cause it?

natesilver: Back in August, I defined these three scenarios:

An actual brokered convention. The nomination is decided before the convention, but there’s genuine uncertainty about who the nominee will be after the last primaries. No candidate has technically clinched the nomination as of the date of the last primary, but the writing’s on the wall.

micah: Yeah, this chat is about No. 1.

natesilver: So where everyone goes to Cleveland genuinely unsure about who the nominee is? In August, I put the chances of that at 10 percent. Now, I’d probably put them at about 20 percent.

clare.malone: I love a good conspiracy theory/out of nowhere plot twist, so I think I’m gonna say 40 percent! Who knows what will happen in the land of Trump! No, I mean, not that high, but I think it is interesting that the party priests are so serious about it.

harry: All right, so here’s my thing: We are 53 days from the Iowa caucuses. Until we actually see how the primary will develop, I can’t say 20 percent. I can say 10 percent. I can see it. It can happen. But the problem is that I’ve heard this song and dance before. In fact, I found seven of the 11 open primaries since 1984 had at least some talk of a contested convention. It happened in 2012, 2008 Democrats and 2008 Republicans, 2004, 1992, 1988 and 1984.

So could this year maybe be different? Sure. But it’s going to take actual results to convince me it’s more than a marginal possibility.

clare.malone: Do you think people just like talking about it? Scare people straight in some way? Toward a more “viable” candidate?

natesilver: I dunno, 20 percent is not that high.

harry: Not as high as the folks at High Times, but to me it’s fairly high. The Eagles had only a 12 percent shot to beat the Patriots last week, according to our Elo ratings. I put a contested convention on about the same plane as that.

micah: Brief public service announcement on the terms we’re using from our managing editor, David Firestone:

A brokered convention is one (historical) form of a contested convention, when state party leaders (or union bosses) acted as brokers for their delegates in the convention horse-trading. Those bosses and brokers no longer exist, so the candidates will have to do the negotiating, along with leaders like RNC Chairman Reince Priebus, House Speaker Paul Ryan, Senate Majority Leader Mitch McConnell, etc., who can hope to use their clout to sway delegates. Of course, there’s no recent historical precedent for that, since all the big rule changes, so no one really knows how this would work.

For more, see here and here (by our own Clare when she was writing for The American Prospect!).

End announcement.

natesilver: You’ve had a lot of near misses, however, Harry. And when there’s a small sample size, it’s important to look at the number of near misses. Put another way, we’ve come way closer in the recent past to having a brokered convention than having someone like Trump win a major party nomination. (Errr … contested convention. Excuse me.)

harry: Citing Wikipedia, a sign of first-rate scholarship. 1980 was a fantasy contested convention. Jimmy Carter had that thing wrapped up. 1984 was perhaps the closest. 1988 wasn’t really all that close; Michael Dukakis was the only guy acceptable to most of the party and clearly won enough delegates. So, one out of 12 times. Seems fairly equal to my 10 percent or so estimate.

micah: Someone explain to me how a contested convention would come about.

natesilver: That part’s easy, or easy enough.

clare.malone: Trump just keeps trucking, right? Gaining steam.

micah: And Trump is gaining steam.

natesilver: It requires two basic ingredients. First, Trump stays in the race, but hits a ceiling in his support. Anywhere from 20 percent to 35 percent of the vote or so would do. Second, the GOP establishment is torn between resigning itself to Ted Cruz and some other choice, most likely Marco Rubio.

Both of those things seem … entirely possible to me.

clare.malone: I’m interested in the idea of seeing the candidates do deals behind the scenes. Who would align with whom?

micah: All the establishment candidates — Rubio, Jeb Bush, John Kasich — could unite! But I guess that’s why Cruz is crucial.

harry: In other words, it requires three candidates sticking around long enough. Nate thinks it’s Cruz, Rubio and Trump. I think Cruz is the most important here, but it could be Cruz, Rubio and, dare I say, Chris Christie.

micah: Yeah, Cruz seems to be the main ingredient for a contested convention; you could see him not playing ball with the establishment to stop Trump.

clare.malone: Was about to say, that guy has a lot of enemies in the GOP. A collaborative atmosphere does not seem like it would be his thing.

natesilver: See, I’d assign a fairly low likelihood to that possibility, Harry. If the establishment has the ability to win the nomination just by choosing between Christie and Rubio, it’s going to pick one of those two rather than risk Cruz or Trump being nominated. Of my 20 percent likelihood, I’d say about 15 percentage points are specifically the case where you have Trump, Cruz and one of [Rubio, Christie, Bush, Kasich].

micah: You need Trump and Cruz.

harry: Why couldn’t it be Christie, Cruz, Rubio and Trump? Why not four?

natesilver: WHAT’S WITH YOUR CRUSH ON CHRIS CHRISTIE, HARRY, ARE YOU A COWBOYS FAN TOO NOW?

harry: Look, I will put up with a lot of your guff, Nathaniel Read, but not recognizing and appreciating my Buffalo Bills fandom is just disgusting. You should be ashamed. Clare knows this, being from Cleveland. We take pride in our NFL teams that don’t win.

clare.malone: Underdogs 4 lyfe.

micah: IDK, I think if Trump is still trucking, the GOP closes its eyes, takes a deep breath and bear hugs Cruz — that’s why I think 20 percent is too high.

clare.malone: Do you think the leaked story was a way of them sending a signal to give that big ole bear hug?

micah: I think it’s too early.

natesilver: But some of the reporting suggests that the GOP is almost as desperate to stop Cruz as it is to stop Trump.

micah: Nate, if both Trump and Cruz are in the race down the road, that means the third person, the establishment candidate, is pretty weak. So they’d be forced.

natesilver: Yeah. The scenario I’m thinking about is where (say) Rubio is picking up a lot of second and third places and not winning very many states. Maybe he’s benefiting a bit from the GOP’s delegate rules, too. But he’s not being impressive enough to have earned a mandate from the establishment.

micah: Is predicting the outcome of a contested convention a fool’s errand? Would the establishment have a good shot of taking down Trump?

harry: They could rake Trump down a peg or two and still have a contested convention. The way it doesn’t happen is if there’s an establishment candidate that consolidates support. To expand on that: Trump doesn’t need to “beat” the establishment for there to be a contested convention. There still might be one even if he tops out at 25 percent of the vote. The way you avoid one is if an establishment candidate can get 45-plus percent of the overall vote, which would probably lead to more than 50 percent of the delegates available.

clare.malone: I think they could take Trump out of things, but they would have to accede to some conservative faction demands in the platform.

natesilver: Yeah, let’s talk Trump. One thing that separates FiveThirtyEight’s position on Trump from a lot other places is that we haven’t necessarily expected his polls to decline immediately. We’re convinced he’s very unlikely to win the nomination; that does not mean he’ll self-combust any time soon.

There are a lot of barriers to his winning the nomination. One of them is whether his support in polls translates to actual votes. We’ll know a lot more about that after Iowa and New Hampshire. But another is that there’s still good reason to suspect he has a ceiling. And unless his ceiling is high enough to the point he can win a majority of delegates or come close to it, the party is going to do everything in its power to trip him up. Including a brokered convention, if necessary. That’s why I thought Costa’s reporting was so interesting (and insightful). It seemed to imply that the GOP would rather have a contested convention than resign itself to Trump winning.

clare.malone: Yeah, Trump said that himself:

“I’ll be disadvantaged,” he continued. “The deal-making, that’s my advantage. My disadvantage is that I’d be going up against guys who grew up with each other, who know each other intimately and I don’t know who they are, okay? That’s a big disadvantage. … These kind of guys stay close. They all know each other. They want each other to win.”

harry: Well, the contested convention gives them some chance of beating Trump. Trump getting a majority of delegates gives them no chance. And if they think Trump is poison, then they’ll hope for anything to avoid him winning.

natesilver: One other thing that people may not know. The GOP’s delegate math is somewhat fuzzy. In particular, there are various sorts of unbound delegates. This is much clearer in the case of the Democrats with their superdelegates, but there are some equivalent cases within the GOP. That maybe gives the GOP a 5-10 percent fudge factor, depending on how you count different categories of delegates. Usually, that fuzzy math helps the establishment to consolidate around a nominee. But the party could also seek to use those delegates to hold out for a contested convention rather than having to nominate Trump.

micah: All right, to close, assign probabilities to each of these eventualities. A contested convention would:

Result in a Trump nomination. Result in an establishment nominee who is currently running. Result in an establishment nominee not currently running. Result in Ted Cruz. Destroy the GOP. Other.

natesilver: No. 5 doesn’t seem to be mutually exclusive with the other choices.

micah: That’s on purpose.

natesilver:

10 percent 35 percent 20 percent 35 percent

harry:

20 percent 40 percent 10 percent 25 percent 5 percent 5 percent

clare.malone:

I think there is no chance of this. I give this a 70 percent probability. I don’t think this happens, either. 30 percent chance destroy the GOP — 50 percent

natesilver: It depends greatly on how close Trump is to winning the nomination. If he comes in with only one-third of the delegates, there’s no way that he gets the nomination. But if he’s at 45 percent, and the convention is a last-ditch effort to prevent him from getting to 51 percent, maybe he still gets over the top.

micah: Nate, you didn’t do Nos. 5 or 6. Clare, you didn’t answer No. 6.

natesilver: What does “other” mean?!?

clare.malone: I second Nate.

micah: An asteroid hits. Or, the GOP doesn’t nominate anyone; they just say “fuck it” and go home.

clare.malone: Mercy ruled.

natesilver: As long as the Warriors win 73+ games before that, I’d be cool with the asteroid.

micah: OK, just do No.5, the GOP is destroyed.

natesilver: The brokered convention would be the symptom of that and not the cause. In terms of the party’s long-run future: a brokered convention is bad, but a considerably less disastrous outcome for the GOP than a Trump nomination.