Why established democracies don't go to war

HostIf you spend any time looking at history, it usually feels like a total mess of one king or emperor trying to take land from another. There are very few things you can actually count on when it comes to how countries behave. But there's one rule that political scientists say is the closest thing they have to a real, solid law.

GuestIt's basically the holy grail for people who study global conflict. The idea is that while democracies are definitely not peaceful in general—they get into fights all the time—they almost never go to full-scale war with each other. A long time ago, in the late seventeen hundreds, the philosopher Immanuel Kant thought this might happen. He argued that if the world was made of republics, we would eventually find a way to have lasting peace. And looking at the data from the last couple hundred years, he was mostly right. It's not just a trend or a lucky streak. It's a statistically significant pattern that has held up even as the number of democracies in the world has grown and grown.

HostThat sounds like a big claim for a field that's usually so full of "it depends" and "maybe." Is it actually a law of nature, or have we just been lucky for a while?

GuestWell, nothing in politics is as certain as gravity, but this is as close as it gets. To understand why, you have to look at how these governments are actually built. Think of it like a set of built-in brakes. In a country run by one person, that leader can wake up and decide to start a war by lunchtime. There's no one to stop them. But in a democracy, the whole system is designed to be slow and messy. You have to go through a legislature, you have people debating the cost, and you have a free press looking over your shoulder. All that friction makes it nearly impossible for a democracy to just launch a surprise attack on another country like itself.

HostBut wouldn't that just mean they're slow to start wars? I mean, they still have big armies. It seems like you could still have two democracies that really hate each other.

GuestThey can definitely dislike each other, but the transparency changes the game. Because a democracy is so loud and open about its plans, it can't really hide its tracks when it gets ready for a fight. If a democracy is moving troops or talking about a draft, everyone knows. This serves as a signal to other nations. Because they can see what's happening, other democracies don't have to live on a hair-trigger. They don't have to be constantly paranoid. Also, there's the matter of who pays for the war. Democratic leaders are directly accountable to the people. Those people are the ones who have to pay the taxes and, more importantly, do the actual fighting and dying. If a leader starts a war that fails or costs too much, they get voted out. That makes them much more careful and risk-averse when they're dealing with other strong states.

HostI hear you on the costs, but leaders are pretty good at talking people into things. We have seen plenty of times where a public is all for a war until things go south. Does the system really stop them if they think they can win?

GuestThat's where the cultural side comes in. Beyond just the laws and the voting, there's this shared set of values. People call this the normative explanation. Basically, democracies are built on the idea of compromise and the rule of law. When two of them have a disagreement, they tend to use the same tools they use at home. They look at each other as legitimate partners. They assume they can work it out through a court or a trade deal rather than a tank battle. But when a democracy deals with a country run by a dictator, that trust is gone. They assume the other side is playing by a different, more dangerous set of rules. That's why a democracy might actually be more likely to strike first against an autocrat—they feel they have to protect themselves against someone who doesn't value compromise.

HostSo the peace only works if both sides believe in the same rulebook. But it feels like a lot of what we call a democracy is pretty new or maybe a bit shaky. Does this rule hold up for everyone, or just the old, established players?

GuestThat's a huge catch. The peace is really only a sure thing among consolidated, or very well-established, democracies. It turns out that countries in the middle of a messy transition from an old system to a new one are actually the most likely to start a war. New leaders in those spots often lean on big, loud nationalist talk to win their first few elections. It's a dangerous time. And some critics think even the peace we see among the big democracies might be a bit of a trick of the light. They say it's a spurious correlation—meaning something else is actually causing the peace.

HostLike what? If it's not the democracy part, what's it?

GuestIt could be the money. We're all so tied together through global trade now that a war would just be bad for business. Or it could be that for the last fifty or sixty years, there has been one big power at the top, the United States, keeping everyone in line. If the global economy shifts or if that big power steps back, this whole democratic peace could turn out to be much more fragile than the data suggests.

GuestThe most recent data shows that as trade networks grow and shrink, the risk of conflict moves with them, which suggests that being friends might have more to do with the bank account than the ballot box.

HostHistorical laws always seem to have a way of breaking just when we start to trust them.

GuestThe data is strong, but the world is always moving.

HostIt's a bit like that old philosopher's hope for a world of republics. Even if the rulebook is what keeps us from fighting, we're still relying on everyone to keep reading from the same page.