Ten Lessons of the Ukraine War from a Classic Master of the Military Art

The war in Ukraine is now well into its second year. Commanders, politicians, military analysts, defense contractors, and journalists are all watching and weighing the lessons for the future. What weapons worked and which were mere hype? Are we now in the age of AI battle? Do sanctions work? Ukraine is badly outnumbered but highly motivated, but will Napoleon’s famous saying, that in war the moral is to the physical as three to one, cause a Ukrainian victory? Or will the crushing weight of Russia’s advantage in size, manpower, and wealth, not to mention its brutal tactics, win out in the end? Can NATO’s – which is mostly America’s – help with weapons and intelligence bring success to Ukraine? Or will Russia outlast a rival that is nearly 5000 miles away (the air distance between Washington and Kyiv) in a war against its neighbor? Finally, how great is the danger of nuclear war?

International lawyers are gathering evidence for war crimes trials. Meanwhile, historians are at work. Some are taking notes for future books. Others, focused on the past, are nodding in sad recognition of the certain terrible old truths about war.

Three things make states go to war: fear, honor, and profit.

There are not many truth-tellers about war older than Thucydides. He was a Greek general and writer who died around 400 B.C. When it comes to war, Thucydides wrote one of the classic books. There is nothing easy about it, beginning with the name of the man and the book, The Peloponnesian War – both are hard to pronounce for an English-speaker. But he had a lot to say then that helps us to understand war now. Events that happened in the past will repeat themselves in the future at some time or other and in pretty much the same ways. Thucydides believed that because he believed in human nature: unchanging, calculating, passionate, and violent.

Here are ten truths about war from Thucydides:

1. Wars aren’t caused by this or that incident, but rather by long-standing trends, grievances, ambitions, and rivalries.
2. Three things make states go to war: fear, honor, and profit.
3. The longer a war lasts, the more it becomes a matter of chance, and the more we are in the dark as to how it will turn out.
4. Everyone wants to have power. You can’t blame people for that. Instead, give credit to people who have the power to misbehave but act with justice instead.
5. The strong do what they can and the weak suffer what they must.
6. War is not so much a matter of arms as of money.
7. Happiness depends on being free, and freedom depends on being courageous.
8. Always base your preparations for the enemy on the assumption that his plans are good. Rest your hopes not on his blunders but on your careful preparation.
9. A good statesman is wise, uncorruptible, and a good speaker. A genius statesman does more: he sees far into the future, makes the right call in a crisis even without having time to think, and explains the right course of action to others.
10. In times of peace and prosperity, people follow higher standards. But war is a violent teacher. It deprives people of filling their daily needs easily, and so it brings them down to the level of their actual circumstances.

These lessons from a classic master of war still resonate today. They speak not only to soldiers, statesmen, and scholars, but to CEOs and anyone who faces conflict.