You can write much of the script for London 2012 already: the tube strikes, the cost over-runs, the security computers that won't work and the Kazakh weightlifters lost in Terminal Five. Factor fat helpings of familiar chaos. But the real problem for the Olympic games we thought we wanted to host is beginning to emerge from the smog over Beijing. Boycotts, boycotts everywhere, and never a pause to think.
Angela Merkel, the German chancellor, has given in already. She won't be going to China this summer, like the Polish prime minister and Czech president. Mr Sarkozy is wandering down the same lightly principled path. Expect more European political defections, plus threatening talk from America's would-be leaders in election year. Darfur began the chat and Tibet has turned it to hubbub; 2008 will be a time for tender consciences to stay away - and 2012 can't fail to catch the same virus. Lhasa is more than another bloody clash between Chinese troops and Tibetan demonstrators. It has set a trend that will bang at own door four years' hence.
But surely, you say, boycotts have always been part of the Olympic game? What about 1980 in Moscow, when America (and many more) stayed away because the Soviet army had invaded Afghanistan? Or Los Angeles four years later, tit for tat? Hasn't China itself sat at home because of Taiwan? True enough: but not the Tibetan point. Sometimes there will be deeds or policies that make withdrawal from sporting contact inevitable. But not yet in Tibet.
The Dalai Lama is an eloquent, gentle man. The struggle for an independent or far more autonomous Tibet attracts attention and sympathy. Beijing has lost friends and failed to influence global opinion. Nevertheless, Tibet remains part of China. No country recognises it as anything else. Its cause is separation, not liberation: and there are plenty of good reasons for caution about that.
Why, for so much trouble, is India so keen to hang on to Kashmir? Because it fears the tides of separatism. Because it fears any negotiation or concession that would encourage others to follow. A standard response. Colombo has only one answer for the Tamils: the same answer as Turkey for the Kurds or Russia for the Chechens. Spain hasn't toed the Washington line and recognised an independent Kosovo: it has the Catalans and the Basques to worry about.
Separatism can seem an obscure cause. How quaint to be so passionate! How ridiculous, in the teeth of globalisation! How odd the old Northern Ireland seems now! Don't mention Scotland! But just watch the tension that flickers and flares as the torch goes through town next weekend.
This is a crisis that starts in the streets. Take a high-profile event and try to use it by disrupting it. Invite confrontation in Lhasa and finish in a swill of boycotts and denunciations. Ask an impossible question and, eventually, get thunderous answers from Europe.
Sympathy for Beijing? Not much. They promised to do better and haven't. But in Chinese terms, a "free Tibet" makes a free Kashmir look easy - and far wider turmoil for China lies that way. So sympathy for the wilder side of Tibetan separatism needs throttling back. If Berlin, Prague and Warsaw want to recognise an independent Tibet, that's their prerogative. But they don't. They are dealing in gestures. It doesn't matter if we don't go to the games, they mutter, the games don't matter.
Cue London 2012. Cue all the other freedom warriors who have seen what attention protest can bring. Don't think that the tiger won't be pulled by its tail again. But surely we are different: everyone loves us, don't they? Not when Stratford provides such a splendid world stage. Not when mushy precedent is set. Prepare, alas, to be very disappointed.
Peter Preston