Whether it is Russian President Vladimir Putin’s threats of nuclear strikes or Chinese belligerence in the Taiwan Strait, the United States seems closer to a great power war than at any time in recent decades. But while the risks are real and the United States must prepare for each of these conflicts, by focusing on the times states fight—and ignoring the times they resolve their conflicts peacefully and prevent escalation—analysts and policymakers risk misjudging our rivals and pursuing the wrong paths to peace.
The fact is that fighting—at all levels from irregular warfare to large-scale combat operations—is ruinous and so nations do their best to avoid open conflict. The costs of war also mean that when they do fight countries have powerful incentives not to escalate and expand those wars—to keep the fighting contained, especially when it could go nuclear. This is one of the most powerful insights from both history and game theory: war is a last resort, and the costlier that war, the harder both sides will work to avoid it.
When analysts forget this fact, not only do they exaggerate the chances of war, they do something much worse: they get the causes all wrong and take the wrong steps to avert the violence.
Imagine intensive care doctors who, deluged with critically ill patients, forgot that humanity’s natural state is good health. That would be demoralizing. But it would also make them terrible at diagnosis and treatment. How could you know what was awry without comparing the healthy to the sick?
And yet, when it comes to war, most of us fall victim to this selection bias, giving most of our attention to the times peace failed. Few write books or news articles about the wars that didn’t happen. Instead, we spend countless hours tracing the threads of Russia’s invasion of Ukraine, America’s invasions of Iraq and Afghanistan, or the two world wars. When we do, it distorts our diagnosis and our treatments. For if we follow these calamitous events back to their root causes and preceding events, we often find a familiar list: bumbling leaders, ancient hatreds, intransigent ideologies, dire poverty, historic injustices, and a huge supply of weapons and impressionable young men. War seems to be their inevitable result.
Unfortunately, this ignores all the instances conflict was avoided. When social scientists look at these peaceful cases, they see a lot of the same preceding conditions—bumblers, hatreds, injustices, poverty, and armaments. All these so-called causes of war are commonplace. Prolonged violence is not. So these are probably not the chief causes of war.
Take World War I. Historians like to explain how Europe’s shortsighted, warmongering, nationalist leaders naively walked their societies into war. It was all a grand miscalculation, this story goes. The foibles of European leaders surely played a role, but to stop the explanation here is to forget all the world wars avoided up to that point. For decades, the exact same leaders had managed great crises without fighting. In the fifteen years before 1914 alone, innumerable continental wars almost—but never—happened: a British-French standoff in a ruined Egyptian outpost in Sudan in 1898; Russia’s capture of Britain’s far eastern ports in 1900; Austria’s seizure of Bosnia in 1908; two wars between the Balkan states in 1912 and 1913. A continent-consuming war could have been ignited in any one of these corners of the world. But it was not.
Likewise, it’s common to blame the war in Ukraine overwhelmingly on Putin’s obsessions and delusions. These surely played a role, but to stop here is to stop too soon. We must also pay attention to the conflicts that didn’t happen. For years, Russia cowed other neighbors with varying degrees of persuasion and force, from the subjugation of Belarus to “peacekeeping” missions in Kazakhstan. Few of these power contests came to blows. To find the real roots of fighting, analysts need to pay attention to these struggles that stay peaceful.
Enemies Prefer to Loathe One Another in Peace
Fighting is simply bargaining through violence. This is what Chinese Communist leader Mao Tse-tung meant in 1938 when he said, “Politics is war without bloodshed, while war is politics with bloodshed.” Mao was echoing the Prussian general Carl von Clausewitz who, a century before, reminded us that war is the continuation of politics by other means.
Of course, one of these means is far, far costlier than the other. Two adversaries have a simple choice: split the contested territory or stake in proportion to their relative strength, or go to war and gamble for the shrunken and damaged remains. It’s almost always better to look for compromise. For every war that ever was, a thousand others have been averted through discussion and concession.
Compromise is the rule because, for the most part, groups behave strategically: like players of poker or chess, they’re trying hard to think ahead, discern their opponents’ strength and plans, and choose their actions based on what they expect their opponents to do. They are not perfect. They make mistakes or lack information. But they have huge incentives to do their best.
This is the essential way to think about warfare: not as some base impulse or inevitability, but as the unusual and errant breakdown of incredibly powerful incentives for peace. Something had to interrupt the normal incentives for compromise, pushing opponents from normal politics, polarized and contentious, to bargaining through bloodshed.
This gives us a fresh perspective on war. If fighting is rare because it is ruinous, then every answer to why we fight is simple: a society or its leaders ignored the costs (or were willing to pay them). And while there is a reason for every war and a war for every reason, there are only so many logical ways societies overlook the costs of war—five, to be exact. From gang wars to ethnic violence, and from civil conflicts to world wars, the same five reasons underlie conflict at every level: war happens when a society or its leader is unaccountable, ideological, uncertain, biased, or unreliable.
Five Reasons for War
Consider Russia’s invasion of Ukraine. What do these five tell us about why peace broke down?
1. Unaccountable. A personalized autocrat, Putin doesn’t have to weigh the interests of his soldiers and citizens. He can pursue whatever course helps him preserve his regime’s control. When leaders go unchecked and are unaccountable to their people, they can ignore the costs of fighting that ordinary people bear. Instead, rulers can pursue their own agendas. That is why dictators are more prone to war.
2. Ideological. Consider Putin again. Most accounts of the current war dwell on his nationalist obsessions and desires for a glorious legacy. What costs and risks he does bear, Putin is willing to pay in pursuit of glory and ideology. This is just one example of intangible and ideological incentives for war that so many leaders possess—God’s glory, freedom, or some nationalist vision.
Societies have ideological incentives too. Unlike the people of Belarus or Kazakhstan, the Ukrainians refused to accept serious restrictions on their sovereignty despite what (at first) seemed to be relative military weakness. Like liberation movements throughout history—including the American revolutionaries—they have been willing to undertake the ruin and risks of fighting partly in pursuit of an ideal.
3. Biased. Most accounts of Russia’s invasion stress Putin’s isolation and insulation from the truth. He and his advisors grossly underestimated the difficulty of war. This is a story of institutional bias—a system that is unwilling to tell its leader bad news. Autocrats are especially prone to this problem, but intelligence failures plague democracies too. Leaders can be psychologically biased as well. Humans have an amazing ability to cling to mistaken beliefs. We can be overconfident, underestimating the ruin of war and overestimating our chances of victory. And we demonize and misjudge our opponents. These misperceptions can carry us to war.
4. Uncertain. Too much focus on bias and misperception obscures the subtler role of uncertainty. In the murky run-up to war, policymakers don’t know their enemy’s strength or resolve. How unified would the West be? How capably would Ukrainians resist? How competent was the Russian military? All these things were fundamentally uncertain, and many experts were genuinely surprised that Russia got a bad draw on all three—most of all, presumably, Putin himself.
But uncertainty doesn’t just mean the costs of war are uncertain, and invasion a gamble. There are genuine strategic impediments to getting good information. You can’t trust your enemy’s demonstrations of resolve, because they have reasons to bluff, hoping to extract a better deal without fighting. Any poker player knows that, amid the uncertainty, the optimal strategy is never to fold all the time. It’s never to call all the time, either. The best strategy is to approach it probabilistically—to occasionally gamble and invade.
5. Unreliable. When a declining power faces a rising one, how can it trust the rising power to commit to peace? Better to pay the brutal costs of war now, to lock in one’s current advantage. Some scholars argue that such shifts in power, and the commitment problems they create, are at the root of every long war in history—from World War I to the US invasion of Iraq. This is not why Russia invaded Ukraine, of course. Still, it may help to understand the timing. In 2022, Russia had arguably reached peak leverage versus Ukraine. Ukraine was acquiring drones and defensive missiles. And the country was growing more democratic and closer to Europe—to Putin, a dangerous example of freedom nearby. How could Ukraine commit to stop either move? We don’t know what Putin and his commanders debated behind closed doors, but these trends may have presented a now-or-never argument for invasion.
Putting the five together, as with World War I and so many other wars, fallible, biased leaders with nationalist ambitions ignored the costs of war and drove their societies to violent ruin. But the explanation doesn’t end there. There are strategic roots as well. In the case of Russia, as elsewhere, unchecked power, uncertainty, and commitment problems arising from shifting power narrowed the range of viable compromises to the point where Putin’s psychological and institutional failures—his misperceptions and ideology—could lead him to pursue politics by violent means.
The Paths to Peace
If war happens when societies or their leaders overlook its costs, peace is preserved when our institutions make those costs difficult to ignore. Successful, peaceful societies have built themselves some insulation from all five kinds of failure. They have checked the power of autocrats. They have built institutions that reduce uncertainty, promote dialogue, and minimize misperceptions. They have written constitutions and bodies of law that make shifts in power less deadly. They have developed interventions—from sanctions to peacekeeping forces to mediators—that minimize our strategic and human incentives to fight rather than compromise.
It is difficult, however, to expect peace in a world where power in so many countries remains unchecked. Highly centralized power is one of the most dangerous things in the world, because it accentuates all five reasons for war. With unchecked leaders, states are more prone to their idiosyncratic ideologies and biases. In the pursuit of power, autocrats also tend to insulate themselves from critical information. The placing of so much influence in one person’s hands adds to the uncertainty and unpredictability of the situation. Almost by definition, unchecked rulers have trouble making credible commitments.
That is why the real root cause of this current war is surely Putin’s twenty-year concentration of power in himself. And it is why the world’s most worrisome trend may be in China, where a once checked and institutionalized leader has gathered more and more power in his person. There is, admittedly, little a nation can do to alter the concentration of power within its rivals’ political systems. But no solution can be found without a proper diagnosis of the problem.
Christopher Blattman is a professor at the University of Chicago’s Harris School of Public Policy. This article draws from his new book, Why We Fight: The Roots of War and the Paths to Peace, published by Viking, an imprint of Penguin Publishing Group, a division of Penguin Random House, LLC.
The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.