The verdict is in: Russia invaded Ukraine for two reasons. One is Moscow’s obsessive pursuit of nationalist and imperial ambitions—unifying the two countries and eliminating a separate Ukrainian identity. The other is Vladimir Putin’s misperception—he is an insulated, overconfident autocrat who misplayed his hand.

These theories are surely true, but years of working in and writing about wars have taught me there’s usually more to the story. Whether it’s a world war, a U.S. invasion or a West African rebellion, observers are quick to focus on passions and mistakes and to demonize leaders who launch a conflict. Yet most wars have strategic roots as well, ones that work in concert with passions and mistakes. Ignoring this makes finding a path to peace difficult.

That is my op-ed in today’s WSJ. You don’t get to pick your headlines, and I am guessing “The Strategic Logic of Russia’s War on Ukraine” will get misinterpreted somewhat.

My view: this is a war driven by Mr. Putin’s psychology, but like all psychological roots of war, they are only decisive when the strategic bargaining space is so narrow. Some will see this as a rationalist take on war, but this is only partly true (and it’s a term I loathe). That’s because it’s not an either/or—strategic and other roots can work in concert, and we should understand this more systematically.

Also, the classic rationalist take on war tends to omit the single most important driver of war (in my mind): unaccountable power. This is an agency problem—leaders who ignore the costs of war to their society, because they can—and so it’s a “strategic” or rationalist cause in a technical sense, but it’s not in the famous duo of asymmetric information and commitment problems.

You never get to say everything you want in 900 words, and so I don’t get to give my other take on the cause of this war: noble ideological intransigence on the side of Ukrainians. Much like Americans during their own revolution, Ukrainians refused the semi-sovereignty offered by a powerful and tyrannical superpower. Some compromises are simply repugnant. This too is an ideological/ psychological account of the war, and I’d say it’s consistent with the strategic story I tell here, explaining Putin’s cruel interests. ALl that will be my next article.

In the meantime, the WSJ piece continues as follows:

For all its pluckiness, Ukraine was weak, a small country with no allies. Its economy had stagnated for decades. Russia had grown economically and militarily while Mr. Putin consolidated control. The countries of Western Europe gave up nuclear power and found themselves at a huge strategic disadvantage versus their energy supplier, Russia. All this gave Mr. Putin immense leverage over Ukraine and Western Europe.

Despite Ukraine’s weakness, recent trends alarmed Mr. Putin and his inner circle. The Ukrainian people had twice tossed out Russia-leaning leaders in revolutions in the past 20 years. Ukraine was a society with which many Russian citizens identified and a powerful example for an uprising against Mr. Putin’s regime.

Mr. Putin could wield his leverage to extinguish the threat, but war would be expensive and risky, so he first tried other means. He spent years influencing Ukrainian politics with money, propaganda, assassinations and support for separatists. These risky investments didn’t pay off—and might have pushed Ukrainians closer to the West and democratic government.

This was a worrisome trend for Mr. Putin. As Ukraine entrenched its freedoms, regime change there became more difficult. As Kyiv obtained more missiles and drones, the costs of invasion grew. Mr. Putin’s leverage over Ukraine was reaching its peak. Russia had one last tool, invasion, and a closing window to use it.

However reprehensible, this was realpolitik. Mr. Putin was telling Ukraine: It’s time to acknowledge Russia’s strength. Give something up. Adopt neutrality. Refuse new weapons. Renounce your ambition to join the North Atlantic Treaty Organization. Grant separatist-controlled regions autonomy. Allow me to meddle in your politics. Most of Russia’s neighbors had been compelled to make similar sacrifices.

There are three interlocked strategic logics at work in this interpretation of events. The first stems from the lack of domestic checks on Mr. Putin’s power. As a personalized ruler, he’s insulated from the costs borne by average Russians—such as the privations of living under punishing sanctions, or sons dying in battle. Since he could ignore these horrors, he was too quick to use violence. This also gave him an incentive to invade. Ukrainian democracy presented a threat not because it would cause harm to ordinary Russians. Rather, it presented a powerful and (to Mr. Putin’s mind) dangerous example for Russians dissatisfied with authoritarian rule. An unchecked Mr. Putin was also free to pursue any emotional attachments to an expansion of Russian power and identity.

The second logic is known as a commitment problem. It’s a classic strategic dilemma that starts with a closing window of opportunity. After every other measure had failed, Mr. Putin could halt Ukraine’s democratic and Western shift only by threatening to attack. Ukraine could avoid the dilemma only by accepting Russia’s political interference. These unjust sacrifices happen all the time, but the popular mood in Ukraine wouldn’t tolerate a politician who made such concessions. Kyiv couldn’t give in to Moscow’s demand that it give up on democracy—a commitment problem.

The final strategic logic arises from uncertainty. Many people, including most military analysts, were surprised by how things turned out. Russian forces proved less competent than expected. Ukraine’s resolve to fight exceeded expectations, as did Western unity on sanctions. We shouldn’t forget how hard all these things were to predict. As every poker player can tell you, when the truth is uncertain and your opponent has an incentive to bluff, the best strategy often is to call—make the other players show their hands. Then you’ll have the truth of the matter. In this fog, Mr. Putin gambled and lost.

Historians and political scientists usually need both psychological and strategic forces to explain wars. Take World War I. Popular accounts stress that naive and nationalistic leaders sleepwalked into war. But there were strategic forces too—Russia’s imminent rise, the Allies’ uncertain resolve, and Europe’s unchecked leadership. These helped propel flawed European leaders into war and explain why they fought for years.

Likewise, in 2003, an unchecked Saddam Hussein had incentives to restart his nuclear research program—a commitment problem exacerbated by uncertainty. Yes, there were ideological incentives, intelligence failures and gross misperceptions on the American side too. Yet popular psychology provides only partial explanations.

In 2022 Mr. Putin was insulated, overconfident and blindly nationalist. But every politician’s aspirations exceed his capabilities. The interplay of Mr. Putin’s domestic freedom to act, multiple uncertainties, and Ukraine’s hard-to-reverse democratic drift narrowed the range of possible bargains to the point that the Russian president’s misperceptions and ideology pointed to war.

Getting this diagnosis right matters, because adversaries use different carrots and sticks with a calculating, unchecked leader than they do with a delusional ideologue. No one should want to risk misjudging Vladimir Putin the same way he misjudged Ukraine.