Pardon the cliche — I think we have come upon a teachable moment. I am referring to the crisis in Ukraine and not just what it teaches us about the future but also what it teaches us about the past. Vladimir Putin has turned us all into Neville Chamberlain. The umbrella, please.

Chamberlain is famous for the Munich Agreement and his statement that by acquiescing to Hitler’s demands, he had brought Britain and Europe "peace for our time." He and the French gave Hitler the Sudetenland, which was the name applied to the substantially German areas of what was then Czechoslovakia. Hitler was a monster but in this case his argument had a superficial appeal: Germans, he contended, ought to be in Germany.

What complicates matters is that we now know — indeed, we soon learned — that for Hitler, the Sudetenland represented mere batting practice. He was soon to invade Poland and much of the rest of Europe, faltering only when he disregarded the bitter lesson Napoleon learned and plunged into Russia. It was a very cold winter.

Putin is demanding for Crimea more or less what Hitler wanted for the Sudetenland: Russians ought to be in Russia. No doubt the Crimean Russians agree, and come March 16, will vote accordingly.That would place a patina of democracy — or at least self-determination — over what is essentially a power grab, but it will be hard to argue that the Crimean Russians aren’t getting the government they want, if not the one they deserve.

So we can see — can’t we? — that Chamberlain was not such a noodle after all. He certainly appeased Hitler. But we are about to do the same to Putin. Just as we — especially our European brethren — can see the logic of Putin’s demands, so could Chamberlain appreciate that the Sudeten Germans might be on the wrong side of the border. Hitler’s homicidal anti-Semitism, among other character blemishes, bothered them not a bit. No one’s perfect, after all.

The fly in my Sudeten ointment is that, like Chamberlain in 1938, we are not sure with whom we are dealing. Hitler soon announced himself, making Chamberlain appear the fool then and forevermore.

But what of Putin? Will he stop at Crimea or, after a pause, plunge into the rest of eastern Ukraine, the part that has many Russian speakers? And then, what next? Will he endeavor to protect ethnic Russians in, say, Estonia? Almost 25 percent of that country is ethnic Russian. How about Latvia, which is about 27 percent Russian?

These are healthy numbers, and if these Russian minorities become endangered, or are merely said to be, a Russian ruler has an obligation to act.

Hitler made things easy. By 1938, he had already purged (murdered) the hierarchy of his vaunted brown shirts, instituted the anti-Semitic Nuremberg laws and, a bit more than a month after he signed the Munich Agreement, launched the vast pogrom known as Kristallnacht. By then, too, he had ruthlessly suppressed all dissent, created the first of many concentration camps and lit the German night with bonfires of unacceptable books.

Putin is no angel, but he has concentrated power without widespread violence or murder. While the Gulag remains mostly a memory, he has sent his opponents to far northern labor camps, such as YaG-14, where the oligarch Mikhail Khodorkovsky was eventually sentenced. Putin is autocratic and kleptomaniacal, but he is not Hitler or Stalin. He has a keen ear for the 24-hour news cycle and must have noticed that the Ukraine story has slipped off Page 1 and, on TV, is not as important as the weather.

Still, it would be wrong to allow Putin’s seizure of Crimea to fall into some sort of memory hole. It would be equally wrong to put concerns about Russian gas for Europe or rubles for London real estate above concerns for the way nations should treat one another. Putin got away with the seizure of Abkhazia and South Ossetia in 2008 (George W. Bush was president then) and now he seems poised to retain Crimea -- at the very least. In the long term, he knows we are short-term thinkers.

This teachable moment has many students. Around the world, there are nations who suffer the grievous loss of this or that strip of land, even worthless rocky islands in the middle of nowhere. What have they learned? Easy. That the rest of us have learned nothing.

Richard Cohen is a writer with the Washington Post Writers Group. He can be reached at cohenr@washpost.com.