In his new book, “Breaking the Two-Party Doom Loop: The Case for Multiparty Democracy in America,” the political scientist Lee Drutman explains the ways in which he thinks American democracy has atrophied or broken down, and what can be done to heal it. “Trump may not so much be the problem,” Drutman writes. “He is instead the symptom of something much bigger.” That something is our two-party structure, which Drutman believes has approached collapse. He believes it has increased partisanship by making everything a binary choice, and that partisanship has itself been worsened by the sorting of the parties into ideologically coherent entities rather than fluid coalitions. It wasn’t so long ago, after all, that the Democratic Party was full of Southern conservatives, and the G.O.P. had a large, moderate wing of elected officials in the Northeast.

Drutman believes that some form of proportional representation with ranked-choice voting could lead to an increase in the number of viable parties, which would in turn reduce partisanship, and eventually gridlock and extremism. Ranked-choice voting, of course, means that voters’ second and third choices matter, too, giving candidates incentives to not alienate their opponents’ supporters. (Hendrik Hertzberg has written extensively for The New Yorker on ranked-choice voting and other potential electoral reforms.)

I recently spoke by phone with Drutman, who is a senior fellow at the New America Foundation. During our conversation, which has been edited for length and clarity, we discussed whether one party is to blame for the current crisis, why ideologically incoherent voting can benefit democracy, and the place of right-wing conservatism in a multiparty system.

It seems as if you are arguing that the problems with our democracy are as much structural as political, if that makes sense—that the politics can be fixed by changing the structures. Is that a fair way of putting it?

I wouldn’t say that politics can be fixed. I think it’s always going to be messy. But a lot of the problems that are most dire in this particular moment are a product of having a genuine two-party system. There is no overlap between the two parties, which is something that I think is quite new in this moment and that is at odds with our political institutions, which demand broad compromise, not zero-sum trench warfare. And it also drives us all crazy, because it really plays into us-versus-them thinking that is inherent in our hardwiring.

O.K. So then what would be a more fair way of putting it?

That a lot of the problems that we are experiencing now are a function of our political institutions and particularly our electoral institutions, which tend to generate just two parties.

What would you say to the argument that regardless of the political system, democracies around the world seem to be breaking down?

I think democracies around the world are all facing certain challenges. The backlash to the financial crisis and increasing globalization, immigration, changing demographics, and urban/rural polarization—those are issues that are affecting all Western democracies. The question is which type of political-party system is better equipped to resolve those dynamics.

The two-party system in the U.S. exacerbates those conflicts in a binary way, and it doesn’t allow for an easy realignment. It’s almost impossible for new parties to emerge, and we just get two tired boxers stuck in a ring continuing to punch each other. The advantage of the multiparty systems throughout Western Europe is that although they’re also experiencing some of these same shocks, the party system can change, and new parties can emerge, and old parties can die. And you can see more responses from the system in which not everything is cast in this binary, us-against-them battle. There are different coalitions that come and go, and new coalitions can form. And it’s messy, but all politics is messy. But I think what you’ve seen is that in most of the Western European democracies, although there is a populist far right that has risen, it has not gained power. In the U.S. it has gained power.

You write in the book, “This is the danger in a two-party system: while it is easier to marginalize the resentments and discontent in the short term, it can backfire in the long term. Marginalization feeds the sustaining populist myth of elite disdain and neglect. And once anti-system political sentiment grows big enough to take control of a major party, democracy becomes unstable.” Aren’t we seeing this in Europe, with the far-right parties saying they are being treated with disdain and neglect and pushed aside from coalitions, and subsequently gaining?

I don’t think it will be enough to gain power. It certainly helped those parties, but to build a winning coalition in a multiparty system, you actually have to build a true majority. And if that sentiment builds to a true majority, then it’s trouble, whatever political system you have.

If you do the math and think about the Republican primary in 2016, you’d say, well, about forty per cent of voters are Republican, or Republican-leaning. About thirty per cent of them wanted Donald Trump. That should be a twelve per cent party. But instead, Trump got the head spot in the United States government and has basically transformed the Republican Party. Because of partisanship being what it is in a two-party system, a lot of folks on the political right said, “Well, I don’t like the guy. He’s kind of crude. But, well, he has the right enemies,” and eventually they’ve warmed up to him. In a multiparty system, there would have been another party for folks to join if Trump had taken over their party. But since there’s only one game in town, a lot of folks have found themselves looking past his obvious shortcomings to just say, “Well, at least he’s better than the Democrats.”

Are there any other specific benefits you think would accrue from having multiple parties?

I think the proportional-voting system that would get us to multiple parties would do wonders for voter turnout. We have quite low voter turnout in the U.S., and that has been pretty stagnant for a long time, despite many efforts to increase turnout. If there are more parties, people are more likely to feel like one of the parties represents them, speaks to them, and they’re excited to vote for it. But even more important, in a proportional system, every vote counts, because there are no swing districts or swing states and you don’t have to live in Iowa or some suburban district near Philadelphia in order for your vote to count. And most people, if their vote doesn’t count, say, “Well, what’s the point of voting?” And even more important, the parties don’t bother to recruit people to vote, because why waste money on recruiting voters who don’t matter? Just focus on the limited ten to fifteen per cent of swing districts that actually matter. People feel like they’re better represented in multiparty systems because they feel like they actually have a party that speaks for them.

One point your book makes several times is that the parties used to be less ideologically sorted, with northern liberals in the G.O.P. and southern conservatives in the Democratic Party. That might have positive effects for partisanship and how the government functioned and so on. But it also seems wrong in the sense that people were often voting for a party that they didn’t really believe in, because of the name of the party and the history behind that party. And that seems not totally healthy for democracy either. Was our democracy in somewhat better shape because people were confused about what they were voting for, or am I looking at it wrong?

No, I think you’re looking at it right. It’s the sad trade-off in a two-party system, which is either you have parties that are incoherent and people don’t know exactly what it is they’re voting for, or you have parties that are quite distinct and then they can’t work together at all, which our political system requires. We are a separation-of-powers system that is set up to require broad compromise and coalition. That was the critique of the bipartisanship of an earlier era—that the voters aren’t able to send clear signals because the parties don’t really stand for anything.