The Russian invasion of Georgia is a damning indictment of Western, and especially European, diplomacy. Though denied membership of North Atlantic Treaty Organization and the European Union, Georgia cannot be denied its geographical and historical membership of the continent and the civilization of Europe.

The Georgians are now paying a terrible price for the failure of European leaders to learn the most important lesson of Europe’s catastrophic history in the last century: the lesson of appeasement.

Cast your minds back 70 years, to 1938. The newly independent state of Czechoslovakia was the only democracy in central Europe, surrounded on three sides by Nazi Germany. Hitler, having been welcomed into Austria — the so-called Anschluss — while the West looked the other way, began to destabilize Czechoslovakia by posing as the defender of the German-speaking minority in the border province known as the Sudetenland.

The British and French were the only democracies in a position to do anything practical for the Czechs. Unfortunately, the French were led by the weak Daladier government and the British by the arrogant Neville Chamberlain, who overestimated his own powers of persuasion and underestimated Hitler’s. Chamberlain made the fatal mistake of agreeing to meet Hitler (hitherto a pariah among statesmen) for talks on the Führer’s home ground.

And so it was that 70 years ago this month, Chamberlain flew to meet Hitler in Bad Godesberg, a small spa town near Bonn. The talks were inconclusive, but one fact emerged: Chamberlain’s policy of appeasement meant that the only question was what price the Czechs would pay to enable the democracies to avoid the war they dreaded. As summer turned to fall, Hitler stoked up the pressure and his propaganda minister, Joseph Goebbels, mocked Chamberlain, who was invariably depicted brandishing a distinctly unmilitaristic umbrella.

Eventually the crisis came to a head at the Munich conference, where Chamberlain, Daladier, and Mussolini carved up Czechoslovakia to give Hitler his greatest triumph to date.

The loss of the border fortifications in the Sudetenland left the rump of Czechoslovakia an easy prey to Nazi aggression. By March 1939, the Wehrmacht was marching into Prague. The Czech lands were annexed as the Nazi Protectorate of Bohemia and Moravia, while Slovakia became a fascist puppet state.

Yet at the time of Munich, Chamberlain believed he had achieved “peace in our time,” as he told the cheering crowd that greeted his return. The image of the aging prime minister of Britain waving the treaty bearing Hitler’s worthless signature became a symbol of the fatal conceit of appeasement — the cardinal error that must never again be committed by democracies when confronted by a determined dictator.

How, then, do we find ourselves in our present predicament? Prime Minister Putin has used the South Ossetians to undermine Georgia exactly as Hitler used the Sudeten Germans against Czechoslovakia. The West sent out all the wrong signals, notably at the April NATO summit, where the Germans vetoed Georgian membership for fear of provoking the Kremlin.

Now that Russia has annexed South Ossetia and Abkhazia, Georgia’s prospective membership of NATO has been rendered even more problematic, because it is unclear where the alliance’s borders would now be drawn in the Caucasus.

If Georgia makes any attempt to recover its lost provinces, Mr. Putin’s panzer divisions are now poised to lay siege to Tbilisi. Having occupied both South Ossetia and Abkhazia, Russian forces threaten the rest of Georgia, while President Saakashvili and his American-trained army are in disarray. Anybody who doubts the Putin-Medvedev regime’s readiness to raze Tbilisi to the ground if necessary need only ponder the hideous fate of Grozny, the capital of the Chechens.

It is certainly true that Mr. Saakashvili miscalculated when he launched his ill-fated attempt to reassert Georgian sovereignty over South Ossetia. But that does not mean the West can wash its hands of this fledgling democracy. If the Rose Revolution can be reversed by force of Russian arms, why not the Orange Revolution in Ukraine?

The pro-Russian regions of eastern Ukraine could easily be mobilized to destabilize democracy there. The Balts, the Poles, and the other nations of Russia’s borderlands feel vulnerable to the same kind of blackmail.

What can — what should — America and its NATO allies actually do? President Sarkozy has flown to Moscow, but this is to repeat Chamberlain’s mistake. The president of Russia, Dmitry Medvedev, stood next to Mr. Sarkozy and denounced Mr. Saakashvili and the Georgian government in vitriolic terms, variously translated as “liar” and “lunatics.” This was in effect an insult to the French president and those he represents: the European Union in particular and Western democracy in general. There must be no more missions to Moscow and no invitations for Russian leaders to G-8 or World Trade Organization summits until the first Russian annexation in Europe since 1947 is reversed.

No, the Russians must simply be told to get their tanks out of Georgia. No ifs, no buts. Only then should talks begin: on the basis that Russia respects the sovereign territory and democratic system of a country that is strategically important for the West no less than for Russia.

If, as the U.S. ambassador to the United Nations, Zalmay Khalilzad, is reported to have said, Foreign Minister Lavrov has warned Secretary of State Rice that “the democratically elected President of Georgia must go,” then Russia is striking a blow against democracy itself.

Chamberlain notoriously thought that it was grotesque to go to war over the issue of Czechoslovakia, “a far-away country of which we know little,” but ended by going to war over Poland under much worse circumstances. If the Russian bluff is ever going to be called, it had much better be sooner rather than later.

Mr. Johnson is the editor of Standpoint.