This article is part of a weeklong series on President Trump’s first year in office.

Steven Levitsky and Daniel Ziblatt are professors of government at Harvard University who had the fun idea of releasing a new, unfortunately relevant book, How Democracies Die. (For those who find the title too sanguine, Die is written in such large letters on the cover that you have to open the book to see who wrote it.) Inside, you will find a depressingly thorough accounting of the ways in which democracy has withered at various times in various countries over the past 100 years. Much of the book focuses on things like norms breached and then disappeared; concerted attacks from anti-democratic forces on crucial institutions; and the rise of political partisanship.

Levitsky and Ziblatt are not entirely pessimistic, because they believe there are things that can be done to rescue democracies on the brink. (See below.) But they leave readers in no doubt that they should be worried about the state of American democracy. I spoke by phone with Levitsky and Ziblatt recently. During the course of our conversation, which has been edited and condensed for clarity, we discussed whether you need a well-thought-out plan to be a strongman, what America still has going for it, and why the Mueller investigation might be a stress test that American democracy cannot pass.

Isaac Chotiner: Was there some aspect of Trump’s campaign, or the early months of his presidency, that made you want to write this book?

Daniel Ziblatt: That’s really the period in which we decided to write the book, during the campaign. We kind of had this eerie feeling we had seen this movie before, with accusations that Hillary is treasonous, or aggressive violence, or later on in the campaign this ambiguity of whether or not he’d accept the results of the election, and this was stuff we had seen before in the political systems that we studied. We could draw on our knowledge of other countries and other places and times to try to understand what was happening.

Steven Levitsky: Those are three things, I think it is fair to say, we never expected to see in a U.S. presidential election.

What historical examples about those three things led you to then write a book called How Democracies Die?

Ziblatt: I studied Spain in the 1930s before the Spanish Civil War erupted. The two main political factions on the right and the left both regarded each other as enemies of the state. In speeches the left would say the groups on the right were really fascist and wanted to undermine the state and those on the right said the same thing about the left. This kind of spiraling rhetoric preceded the Democratic breakdown in Spain. Similar kind of thing in Germany in the late 1920s.

As you researched the book, did you get more or less concerned about what you were seeing in the U.S.?

Levitsky: I think more concerned about some things and less concerned about other things. I’ll give you one example. I am, even relative to when we wrote the book, shocked and surprised by the degree to which the Republican Party is willing to go along with Trump’s shenanigans. We had expected, and I would have expected a year ago, much greater Republican resistance to Trump. The fact that there is almost none and any Republican who is taking Trump on has basically been defeated, that makes me more worried.

Right, I think over the past year some things have gone better than expected—things having to do with incompetence, having to do with the resilience of certain institutions—but the one that does feel the most terrifying to me is what you said about the GOP just going along with him.

Levitsky: That’s right. I think the courts have largely done their jobs; I think we mostly expected that. But Trump’s weakness and Trump’s political weakness, his lack of popularity, and his sheer incompetence have obviously benefited democracy. No question about it.

Ziblatt: I agree with Steve on the Republican abdications, which have made me more worried and surprised. But on the other side of the ledger, I would say one thing that has given me hope, and I think Steve as well, is a kind of robustness … some sense of robustness in civil society measured by the legal profession, measured by the journalists and media, and they have been incredible. So in this sense, these are the kinds of institutions that have risen to the occasion.

I think we all agree Trump has very authoritarian instincts. At the same time, I think it’s pretty clear that he is not consciously thinking, “Oh I want to establish some sort of authoritarian system and this is my plan for doing so and I hope that in 2020 I am a dictator and elections are canceled.” I could be wrong, but I really don’t think he or the people around him are thinking in those terms. And that does offer me a ray of hope. I’m wondering if you guys agree, but then I’m also wondering if you think that maybe that’s irrelevant—that people who become strongmen, they don’t necessarily start out with that plan, but by weakening institutions, that’s where we end up. And maybe there are historical examples one way or the other.

“Really confrontational efforts to impeach Trump are going to reinforce the kind of norm erosion we’ve been suffering from since the 1990s.” — Steven Levitsky

Levitsky: It’s less dangerous that Trump doesn’t have an authoritarian plan than if he did, and there are some autocrats that come to power with a plan. But there are also historically many autocrats that don’t come to power with a plan. Maybe the most obvious case to me is Alberto Fujimori in Peru. He was a political outsider, a political novice, who was elected with an anti-establishment populist rhetoric. He continued that rhetoric in office, certainly didn’t have a blueprint but picked fights with the judiciary, picked fights with Congress, picked fights with the media, and you had this spiraling effect in which he said scary things and the courts and Congress upped the ante and were very antagonistic toward him. And eventually, it spiraled out of control to the point where he called out the tanks.

Now, Trump is not going to be able to call out the tanks. But it’s a case in which you sort of get unanticipated effects of a novice coming to power with very antagonistic discourse that scares the establishment. The establishment then pushes back. The president then feels deceived and pushes back even further. Again, Trump is not going to be able to call out the tanks, but several years of conflict between presidents and different elements of the establishment could easily weaken our democratic institutions to the point where somebody with a plan can do more damage next time.

What things do you guys have your eyes on the most, going forward? Is it the 2018 elections? The 2020 elections? The resilience of certain institutions?

Ziblatt: I think the 2018 elections are crucial and the Democrats need to do well in order to conserve some kind of check. I think the second point is what lessons the Republicans draw from the electoral success of the Democrats. Do the Republicans then realize they need to separate themselves finally with Trump? Because even if Democrats sweep the House and the Senate, any need to kind of impeach Trump unilaterally without Republican support is going to be damaging for American democracy in the long run. So in some ways I think it is really critical to continue to focus on the Republicans and to hope and expect that the Republicans at some point, once they see the electoral cost of continuing to align themselves so closely with Trump, will then break with him.

Levitsky: I think there are two things that we are keeping our eye on, one is more short term and one is more long term. One is defeating Trump and the other is shoring up our democracy, and the two are related, but they are not completely related. Obviously, 2018 and 2020 are critical for curbing and ultimately defeating the Trump administration, removing from power a government that is not fully committed to democratic practices. That is incredibly important. But, one of the things that we found in the book and that we believe very strongly, is that the problem facing American democracy, problems of norm erosions and intense polarization, predated Trump and are very likely to persist after Trump. In fact, the way that we remove Trump is going to have an impact on the quality of our democracy going forward. Really confrontational efforts to impeach him are going, as Daniel pointed out, to reinforce the kind of norm erosion we’ve been suffering from since the 1990s.

So we are keeping an eye obviously on Trump, but we are also keeping an eye on the underlying polarization that is beginning to rip our institutions apart. And I think, getting back to what Daniel said, the future of the Republican Party is critical. The Republicans have to eventually become a party that represents more than small-town white Christians. It has to be a party that can represent a more diverse sector of American society. And until that’s the case, we are likely to have our parties be polarized along racial and religious lines, and that is trouble.

How do you think about the Russia investigation in this context? I think the investigation has served as a kind of lifeline for people who want to see Trump not be the president, but it’s also caused me to have two distinct varieties of fear. The first is that Mueller will say that Trump committed some very bad crime and Congress will do nothing about it, which I think in terms of a norm erosion would be extremely worrying. And the second is that the investigation will not go anywhere conclusive involving Trump, and Democrats will impeach him anyway when they get into office, which I think could also have a bad effect, although not as bad as the first option.

Levitsky: I think you’re right. There are many ways in which this can end up being problematic in terms of our democratic norms. I think the best-case scenario, which isn’t that likely, is a Nixon-like scenario in which Mueller comes up with something pretty overwhelming and a big enough faction of the Republican Party defects so that you get bipartisan consensus behind impeachment and we end up with a sort of norm reinforcing outcome. That doesn’t seem highly likely for the reasons that you say. If there is a partisan division in the reaction to the Mueller findings, which seems fairly likely given the level of partisan polarization, it will probably make things worse.

[The investigation] provides Washington, it provides us, with a viable means to remove Trump and that’s double-edged, right? If Trump is in danger—either because he’s unfit for office or because he’s an authoritarian—that’s potentially a good thing. But any kind of irregular removal of a president before his term is a shock to the system—something that is a fundamentally destabilizing event.

Ziblatt: One way to think about impeachment is that it may become necessary, but if it’s regarded as simply a partisan tool, it’s just the next turn in the kind of death spiral of polarization where each side accuses the other side of exploiting maximum advantage. So that’s why we have to be very cautious.

Levitsky: Right, if a large enough faction of the Republican Party thinks, “Fuck you,” and interprets the impeachment of Trump as a coup, we’re in serious trouble.

Is there any democracy that you would have ranked as highly as you ranked the United States as a democracy in 2016, whatever ranking that is, that’s fallen victim to authoritarianism in your case studies?

Levitsky: No, there are actually very, very few established democracies, democracies that have been fully democratic and that have been around for, say, 20 or more years, very few of them in the history of the world have collapsed. Uruguay is one, Chile is another, Venezuela is a third, maybe Hungary depending on how you interpret it these days. But none have been as stable or as democratic as the United States.

Hey! A cause for hope.

Levitsky: In our book, we are not making the argument that democracy is in imminent danger. All we’re saying is that if you’d asked us five years ago or 10 years ago we probably would have laughed off the question, and now we think there is a risk that is worth concerning ourselves with.

Ziblatt: I would just add to that, one of the strongest findings in social science is the level of GDP per capita and its correlations with democratic stability. Given the U.S.’s national wealth, the probability of democracy collapsing [is] very, very low. But that again, that’s based on the record of the past 50 years so who knows? Using the past as record, though, we should feel some sense of security.

Using the past as record, we wouldn’t have elected an authoritarian television star.

Levitsky: Right, there is a sense among many different observers, many different scholars, that we are skating onto some new territory.