KEY POINTS:
Safety is our top concern," said China's Vice-President Xi Jinping in late July, pointing to the deployment of 100,000 troops around Beijing and the surface-to-air missile batteries that protect the main stadiums as proof of the regime's determination to ensure that no terrorist attack would disrupt the Olympic
Games.
But it couldn't stop two equally determined Uighur militants from killing 16 Chinese police and injuring another 16 in an attack on a border post near Kashgar.
True, Kashgar is in the far northwestern province of Xinjiang, 4000km from Beijing. But if two men armed only with hand grenades and knives could do that much damage there, what is to stop others from doing it in Beijing? Certainly not surface-to-air missiles.
The best way to prevent terrorist attacks is to remove the grievances that often motivate them, and to penetrate the terrorist organisations with informers. China hasn't done very well on either front.
In Xinjiang as in Tibet, it has inundated the local population with a wave of Han Chinese immigrants who live essentially separate and far more prosperous lives, and have created great resentment as a result.
The number of Chinese immigrants in Tibet and Xinjiang is so great that they threaten to turn the original populations into a minority - in Xinjiang they have already done so - and that is bound to stir fears of cultural and linguistic extinction in the colonised population.
That was the real reason for the explosion of anti-Chinese violence in Tibet earlier this year, and it has been the motive power behind Uighur separatist movements in Xinjiang for 20 years now.
Ironically, the reason for the huge influx of Han Chinese immigrants is a ham-handed effort to quell separatist sentiments in the two provinces. Most Chinese believe that their country has ruled both Tibet and what used to be called East Turkestan since time immemorial, but in practice they only came under direct Chinese control in the mid-18th century, around the same time that the British were seizing control of India.
So if Beijing doesn't want its western territories to go the way of British India eventually, then it must find a way to bind Tibetans and Uighurs to China. The solution, Beijing reckoned, was lots of development and rising prosperity, which would reconcile both Tibetans and Uighurs to Chinese rule.
Maybe it would have, too, if the subject peoples had actually shared in the prosperity, but they didn't. Educational levels and technical skills were gravely lacking in the indigenous populations, so the real (although probably unintended) effect was to draw in millions of Chinese immigrants who did have the necessary skills. And it was they, of course, who got all the good new jobs.
In 1945, some 90 per cent of Xinjiang's population were Uighurs, a Muslim, Turkic-speaking people who are closely related to the other Muslim populations of Central Asia. (Indeed, the Uighurs of Xinjiang and the Uzbeks of northern Afghanistan and Uzbekistan can actually understand each other's languages).
Now the Uighurs are down to eight million out of 19 million - less than 45 per cent of the population and falling fast. As in the case of Tibet, there has been very rapid urbanisation, but most of the native population lives in ghettoes that are little better than slums, with no hope of getting the good jobs that are monopolised by Chinese immigrants. The difference between the two regions is that in Xinjiang there have been sporadic terrorist attacks against Chinese people and interests since the early 1990s.
Tibet is isolated by geography, culture, religion and language. It has no strong affinities with anywhere else, which largely explains its relative political passivity between the big 1959 revolt and this year's disturbances.
By contrast, Uighurs have strong historical, cultural, religious and linguistic links with the other Central Asian groups - all of which got their independence when the Soviet Union collapsed in 1991.
That example, of course, was very seductive, and so a wide variety of Uighur separatist groups have carried out occasional terrorist attacks both in Xinjiang and in China proper over the past two decades. The rise of "Islamist" terrorism latterly has given them a more coherent ideology than mere nationalism, and also some useful contacts in the more distant parts of the Muslim world.
They have only killed a couple of hundred people in 20 years, but they remain a serious headache for the Chinese regime. In all that time, Beijing has not succeeded in penetrating and breaking up the Uighur groups who are waging this violent separatist campaign.
Part of the reason is doubtless that these groups are small, numerous and fragmented, but they are also increasingly difficult for the Chinese intelligence services to penetrate because they have become more and more Islamist (as opposed to merely nationalist) in their ideology.
So could Uighur separatists, or even Tibetan ones, carry out a terrorist attack in Beijing during the Olympics? Of course they could.
Nothing too spectacular, of course. No hijacked airplanes crashing into stadiums. But two men with grenades (or two women, for that matter) could do a lot of damage, and even 100,000 troops would need some luck to stop them.
* Gwynne Dyer is a London-based independent journalist whose articles are published in 45 countries.