Last Monday, seven members of the Labour Party resigned over concerns about Jeremy Corbyn’s leadership. They will remain in Parliament as independents. (Two more members resigned from the Labour Party later in the week.) Their decision was sparked by Corbyn’s unwillingness to come out strongly against Brexit, and in favor of a second referendum, which they hope might reverse the 2016 vote. (Shortly after this interview was posted, the Labour Party released a statement that it intends to move forward with a second referendum if the government’s Brexit motion does not meet certain demands.) They also claimed that Corbyn has tolerated rising anti-Semitism in the Labour Party; one of the departing members, Luciana Berger, has received a great deal of anti-Semitic abuse. How significant are their departures, and where does this leave the Labour Party on the eve of Britain’s scheduled departure from Europe, on March 29th?

To talk about these questions, I spoke by phone with David Runciman, a professor of politics at Cambridge University, and the author of, most recently, “How Democracy Ends.” During our conversation, which has been edited and condensed for clarity, we also discussed what Theresa May will do if she can’t get a Brexit deal through Parliament, whether Corbyn’s skepticism about remaining in Europe is ideological or tactical, and why British politics has become such a nightmare.

How important or meaningful is this Labour Party split?

It’s one of those events that’s been coming for such a long time that it’s tempting to write it off and think it’s a bit of a non-event. There are only seven of them, not particularly well known. But I think it’s important. It’s almost certainly the beginning of something, because the party system in the U.K. is frozen. It was waiting for something to loosen it up, so we’ll have to see, but it’s a big deal.

I assume you think it’s a big deal because the reasons it’s been coming for a long time are big deals. Is that right, and what are those reasons?

Yeah, it’s because we’re in this weird situation. The two main parties, Conservative and Labour—eighty per cent plus of voters voted for them or give their support to them. Then, in the last poll, sixty-eight per cent of people said they didn’t believe either of the two main parties spoke for them. A lot of voters feel trapped. They have to make a choice between these two options, and they hate both options, because they feel each party is being captured by a narrow group.

Particularly, there are a lot of voters who feel that a Jeremy Corbyn Labour Party is not how they want to vote, and yet they don’t feel they have an option to vote anywhere else. It’s that, and then it’s Brexit. We all feel we can’t go on like this, and yet we’ve been going on like this for nearly three years, and we’re waiting for the thing that signals that the unravelling has begun.

The historical precedent that most people are using for this is when some Labour Party members split off in the early eighties, to form a more centrist group. Does that make sense as a historical analogy?

I think it misses two things. That was a group who were much more prominent, particularly three of them. Roy Jenkins, David Owen, and Shirley Williams were among the most prominent politicians of their time. That had leadership. This does not have leadership. There is no one here who looks like a future Prime Minister. There is no one here who looks like they are going to take this movement forward themselves. A lot of people have noted that where that centrist breakaway failed was that it only took support from Labour. They were all Labour people, as now, but there was hope they would bring in Conservatives. What we don’t know at this time is whether there is movement on the other side, too. [Soon after our conversation, three Tory members of Parliament left their party to join the new centrist group.] It’s parallel with the U.S.: people are profoundly frustrated with the two-party system. Yet it is profoundly tribal.

There’s been some frustration among people in the Labour Party that Corbyn will not come out in favor of a second referendum to reverse Brexit, and that his affect and tone when he talks about Brexit are not the affect and tone of probably eighty per cent of Labour voters—that Brexit is a catastrophe, which must be resisted at all costs. Where do you think Jeremy Corbyn is right now on Brexit, both strategically and in terms of what he actually thinks about it?

I think how you describe it is how most people see it. This has been true right from the get-go, during the campaign itself—his affect, his tone, was not that of someone who believed in what he was saying. There is general acceptance now that, given the choice, Corbyn wants out of the E.U. It’s also true that, over time, the Labour Party’s members and voters have moved more and more in polling against Brexit. There was a period where Labour was torn; there was this feeling that many of its metropolitan, young, college-educated supporters were against Brexit, but its heartland was for it. There’s more and more evidence now that the Labour vote as a whole clearly thinks that Brexit is a bad idea.

The thing about Corbyn is that he’s never been strategic. He just plows on. What’s interesting about this moment is that it probably forces him to face some strategic choices, because this group, this breakaway group, is a pro-second-referendum group. There’s a possibility that Corbyn sees this as the beginning of the sort of sorting process whereby the really strong pro-second-referendum people are leaving the Party, and it makes it easier for him to hold his line.

The other thought is that, if this is the issue that actually breaks the Party, and the nineteen-eighties example is anything to draw on—if it prevents Labour from winning a general election because it splits the vote on the left—he has to finally face up to the fact that his convictions are not the whole story here. He’s not there yet. We’ve been through this farcical series of votes in the Commons, each one of which is meant to be the moment of truth.

Corbyn’s defenders would say, first, that it’s not clear how to get to a second referendum, so, essentially, what do you want him to do? And second, as you said, part of Labour’s heartland was always pro-Leave. He got some of their votes. So they might say that what he’s been doing over the past year is a smart tactical maneuver to seem like he’s open to people who wanted Brexit and to not seem like he’s betraying a democratic vote. Do you think there’s any truth to that argument?

Not that he puts it like this. Part of the problem is that he never clearly expresses the argument you just made.There is a strong case for saying a second referendum still doesn’t really make sense—no one knows how to do it, even if the House of Commons agrees in principle that it wants a second referendum, and it’s very unlikely to agree on the details of that referendum, what the choices are, what the question is. There is a case for saying that Corbyn is being a kind of realist here. It’s also true that the Labour Party can’t win power again if it doesn’t hold together. It has to hold its pro-Brexit supporters with its pro-Remain supporters. What’s happened this week is evidence it’s not holding together anyway under these conditions.

The problem with Corbyn is, even if what you just described makes sense, the way he comes across is as a politician who’s not thinking this through pragmatically, who’s not made a judgment about what’s realistically possible. He’s just doing what he’s done throughout his career, which is holding the line on the things that he’s always believed in. The fear from many people on the Labour side is that he could keep going as the Party fractures, a long way, before he finally recognizes the risk that he’s running. There’s no evidence that Corbyn is the kind of politician who wakes up to the need to be flexible in time.