NATO, the North Atlantic Treaty Organisation, is a remarkable case of institutional survival in the face of changing circumstances. It was created in 1949 to protect Western Europe from the Soviet threat, and in 1989 the Soviet threat vanished.

Yet NATO not only survived the collapse of the Soviet Union but expanded, taking in all the former satellite states of Eastern Europe and even the Baltic republics that had been part of the Russian empire for more than 200 years. But the Georgian debacle could break NATO.

In those Eastern European countries that were so recently ruled from Moscow, the presence of Russian troops in Georgia has reawakened all the old fears. Last Thursday, Poland hastily agreed to let the United States place antiballistic missile sites on its soil, on condition that there must also be a full-fledged U.S. military base in the country. Why? Because then, if Russia attacked Poland, the United States would automatically become involved.

What drives all this is historical memory, not genuine strategic calculation--Russia is not planning to attack Poland--but the emotions it evokes are very powerful. That's also why 50 Estonian military volunteers have now arrived in Georgia (although nobody knows quite what to do with them).

The rhetoric in the new NATO members has been almost as hysterical as that in Georgia itself, where President Mikhail Saakashvili has been calling the Russians "21st century barbarians" who "despise everything new, everything modern, everything European, everything civilised".

Similar rhetoric pervades the parallel universe of the U.S. media, where the fact that it was Georgia that started this war by unleashing a merciless artillery barrage on South Ossetia and then invading it has been virtually erased from the story line.

Very few Americans know that there was only one battalion of Russian peacekeeping troops (less than a thousand men) in South Ossetia when the Georgian tanks rolled in less than two weeks ago. It's all "plucky little Georgia" and democratic values versus the Russian bear.

It's a rousing morality tale that hits all the right notes for an American sensibility, and it's not just Georgia's PR firms that are pushing this line. It's also the U.S. State Department and the Pentagon, which had been building Georgia up as a key U.S. ally on Russia's southern flank. Yet US Secretary of State Condoleezza Rice looked deeply uncomfortable last Friday in Tbilisi as she stood beside the ranting Saakashvili.

Perhaps she was pondering the fact that while the "new Europe" of former Soviet-bloc countries uncritically backs Georgia and the U.S. commitment there, the "old Europe" of Germany, France, Italy, and their neighbours mostly does not.

This is a problem if she wishes to pursue her goal of bringing Georgia and Ukraine into NATO, since "old Europe" is the core of NATO, with three times the population and five times the wealth of "new Europe".

Any American secretary of state can rely on the reflex loyalty of the British government, at least in its current New Labour configuration, but none of the other great states of Western Europe thinks that having a confrontation with Russia over Georgia is a good idea. In fact, they think it's crazy.

Angela Merkel, the German Chancellor, put it quite carefully after she met Russian President Dmitry Medvedev on Friday: "Some of Russia's actions were not proportionate [but] it is rare that all the blame is on one side. In fact, both sides are probably to blame. That is very important to understand."

The Italian government warned against trying to build an "anti-Moscow coalition". French Foreign Minister Bernard Kouchner works for the most pro-American French leader in recent history, President Nicolas Sarkozy, but he still said: "Don't ask us who's good and who's bad here. We shouldn't make any moral judgments on this war."

This will all be seen as "appeasement" by the neoconservatives who still rule the roost in Washington, but many in Western Europe would call it common sense. The Russians will stay in Georgia until they have dismantled the Georgian army and navy bases that could threaten the ethnic enclaves of South Ossetia and Abkhasia again, removing all the new American weaponry that gave Georgia an offensive military capability, and then they will withdraw to the enclaves as the ceasefire agreement requires.

Sarkozy brokered that ceasefire, and he agreed to write those clauses into it. He knew that they allowed Russian forces to stay on Georgian territory until the military threat had been nullified, and he accepted them. He did so because he did not really see Russia as an aggressor in this crisis (although he will not contradict America publicly by saying it in so many words.) But if the U.S. pursues its goal of bringing Georgia and Ukraine into NATO, there are only three options.

If "old Europe" digs in its heels and refuses, on the grounds that it does not need Russia as an enemy, then either the United States drops its demand, or NATO breaks up. The third alternative (and perhaps the likeliest) is that "old Europe" agrees to let the two former Soviet republics join--but with the unspoken reservation that they will never actually go to war with Russia to protect them.

That would be a less dramatic end for NATO, but it would be an end. A two-tier alliance is no alliance at all.