War is a stupid idea.

Fighting is a bad way to resolve disagreements. If two countries want the same land, it is almost always less costly to each side to split it than to fight. The same is true if they are arguing over a shared natural resource, like oil. Fighting costs lives and money, with an incredibly uncertain payoff when the dust settles.

And yet wars persist, both within nations and, as appallingly demonstrated by Russia’s devastation of Ukraine, between them. Why? Why do governments and private armed groups still resort to violence when it’s so often mutually destructive?

That’s the question Chris Blattman’s new book, Why We Fight, seeks to answer. Blattman is an economist and political scientist at the University of Chicago, and he has studied the roots of violence in many different contexts. In academic work, Blattman and his coauthors have examined the roots of child soldiering in Uganda, the potential of cognitive behavioral therapy to prevent violence in post-war Liberia, and the policy choices of drug gangs who govern neighborhoods in Medellín, Colombia.

Why We Fight is an effort to summarize what he and other social scientists have learned about violent conflict, both between and within states: where it comes from; if it can be prevented; and how to stop it once it’s begun.

Blattman and I spoke for this week’s episode of the Vox podcast The Weeds. A transcript, edited for length and clarity, follows. Note that our conversation occurred on April 7, so we didn’t cover the past couple weeks of developments in Ukraine. As always, there’s much more in the full podcast, so listen and follow The Weeds on Apple Podcasts, Google Podcasts, Spotify, Stitcher, or wherever you listen to podcasts.

Dylan Matthews

You start from a standpoint that is kind of surprising for a book about war, which is that war usually is a bad idea, it usually isn’t in anybody’s best interests, and most conflicts are resolved peaceably. Can you explain that organizing framework and why you think that’s important?

Chris Blattman

It is kind of amazing how much attention we pay to violence. We want doctors to pay a lot of attention to sick people, but then we don’t want them to forget that most people are healthy.

For example, two weeks into Russia’s invasion of the Ukraine, India accidentally lobbed a cruise missile at Pakistan and nothing came of it, and we shouldn’t be surprised at that. Likewise, schoolchildren will learn about the US invasion of Afghanistan for decades, [but] very few kids will be taught about the US invasion of Haiti in 1994, which ended before it began. Colin Powell went to the coup leader [Raoul Cédras] who ousted a democratically elected president, showed him a video of US troops loading into planes and taking off and said, “This isn’t live. This happened two hours ago,” and he sort of surrendered right there.

All of these things are happening all the time. And they’re happening for a pretty simple reason. If you’re Pakistan [after India’s missile launch], it’s just going to be ruinous if you go to war over this, even if you think it might not have been an accident. And this military leader in Haiti … It wasn’t just that the US was strong and Haiti was weak. That was part of it, but we know that weak parties can mount insurgencies. I think he just looked at [the situation] and he said, this isn’t going to be worth it, because I can basically use whatever bargaining power I have to get some kind of deal. [The US government wound up giving the coup leader over $1 million to leave.]

That’s just the normal everyday business of what happens, precisely because war is so costly. Peace has this gravitational pull, from all the costs of war. So war only happens because some other force yanked it out of that orbit, which is actually pretty hard to do.

Dylan Matthews

You list five explanations for war, which are all explanations of how bargaining breaks down and why people can’t reach agreements peaceably. Could you walk through those five?

Chris Blattman

I call them:

1. Unchecked leaders
2. Intangible incentives
3. Misperceptions
4. Uncertainty, and
5. Commitment problems

Three of them are more strategic in nature, and then two are more psychological.

Let me just start with a couple examples that I think are the most intuitive. We live in a world with a lot of autocrats, and even if they’re not autocrats, we live in a world where leaders are not totally constrained by their people, which means they don’t have to do the thing that’s in the interest of their group. This especially matters for someone who is completely unaccountable, like a personalized dictator, which Vladimir Putin has increasingly become.

If you’re a personalized dictator, you don’t have to consider all these costs of war. You consider some of them, but you consider a much narrower range, so you’re much more ready to use violence. Sometimes leaders, particularly dictators, have a special incentive to invade or attack that their group doesn’t share. In Liberia, maybe the warlord Charles Taylor thinks he’s going to get more diamond profits by keeping the war going. Or maybe Putin thinks that too — to keep his regime of control the war needs to keep going. That’s one example of a very powerful thing that can yank us out of that peaceful orbit.

Another, which is related, I call intangible incentives. What if the group or a leader — or in particular the dictatorial, personalized ruler — is seeking some ethereal benefits, something they value? That gives them a strong incentive to go to war. It’s not a material incentive like diamonds or something strategic, like “I need to gain this territory in Ukraine or exterminate democracy there because it’s going to threaten me.” Rather, it’s this nationalist ideal of a unified Russia. Or, in Charles Taylor’s case, a nationalist ideal of a unified West African Republic that, by the way, he would rule. It could be personal glory, like wanting to be the next Catherine the Great. It could be the desire to exterminate a heretic, or in service of some kind of religious or ethnic ideal. If you value this thing that only war can bring you, it’s going to yank you out of the peaceful orbit.

“Misperceptions” includes all the ways war happens by mistake. Uncertainty is about times when we don’t know the strength of our opponent, we don’t know their resolve, so it seems like the optimal choice to fight. Commitment problems are mostly cases where there’s some way we can avert our opponent from being strong in the future. It actually pays to invade now to lock in our advantage forever. That can overcome the costs of war.

Dylan Matthews

We’re having this conversation as a war in Ukraine rages. Just before the war broke out, you wrote a short post asking the question of why diplomacy didn’t work, why the countries hadn’t been able to come to a deal. Looking back, how do you think about that question? How do you apply some of the lessons in this book to that context?

Chris Blattman

I know exactly how to apply each of the lessons in the book. What I don’t know is which ones are correct.

What it comes down to is you either think Putin and his cabal are being strategic, or they’re not. I always lean on this side of [strategy]; fundamentally they’re not bonkers. Certainly in week four, they’ve woken up and they’re becoming strategic.

But at many lunch hours, I knock on the door of my colleague Konstantin Sonin, who used to be the provost of one of the most major universities in Moscow. He’s a game theorist, so he’s the kind of person who’s biased to think that everything is strategic, and he thinks it’s completely non-strategic. He thinks [Putin’s] inner circle has basically gone downhill in quality of thought and quality of individuals and experience, and that they’re both mass-deluded and ideological. He puts in the misperceptions and the intangible incentives, and that’s enough for him.

I lean more towards the strategic camp. We can all understand Konstantin’s point of view because it’s what we read in the paper every day. I’m always suspicious of it because it gives those people very little agency. It denigrates them. It makes us feel superior.

I think it comes down to Putin’s unchecked-ness: the fact that he is not responsible for the costs [of the war], and he has some private incentives, in terms of the preservation of his regime, to exterminate democracy in Ukraine. There’s uncertainty; he got bad draws and Ukraine got good draws. There’s maybe a little bit of a commitment problem, where he could see a point where [Ukraine] is more democratic, closer to the West, maybe even armed with long-range missiles by the West and thus impossible to invade, and so the window of opportunity is closing.

I think those are really important to understanding the war. But for the record, Konstantin totally disagrees with me.

Dylan Matthews

The US is still processing what happened on January 6th last year. On the extreme end, your colleague Barbara Walter has a book raising the possibility of widespread political violence in the US. Even if not a Liberia-style civil war, then widespread terrorism and street violence. I’m curious how you think about that question, especially because I left your book oddly hopeful about our odds of finding peace.

Chris Blattman

Barbara’s not the extreme end — there’s people who think there could be full-scale civil war. Barbara’s more like, “At worst this is probably going to look like the Irish troubles, and that’s not assured.” She’s definitely more pessimistic than I am. I agree with a lot of what she says. We just have very different probabilities. We can all look at the same evidence and disagree.

Again, it comes down to these costs [of war]. These costs are very high and we have a lot of institutions that have not been politicized and are very good at internalizing these costs, and therefore will work very hard to avoid them. The thing that would push me to be as pessimistic as Barbara is if those institutions, like our military and our Supreme Court and police forces, were more split, or more unaccountable, and thus were not internalizing these costs of violence. But I actually have found those institutions to be amazingly resilient in a polarized age. I draw some optimism from that.