Protest and dissent in Tibet in March and April upset China's leadership which seethed with rage at Zhongnanhai palace in Beijing. While the riot police got on with the shooting and beating in Lhasa and elsewhere, albeit with more restraint than in the past reflecting new tactics for dealing with unrest, there was no restraint in official communiques of colourful and rich vitriol and invective usually found in cheap fiction.

A perplexing choice of words for a regime which tries to culture an image of a sophisticated and modern state while never wasting an opportunity to remind any and all that it stand high on the 5,000 years of civilisation in the lands now called China. Neither the crude rhetoric which gushes in torrents whenever Beijing feels slighted nor the attempts to bask in the supposed glory of millenia of imperiums bespeake of confidence, nor necessarily much sophistication, within the inner sanctums of the Chinese Communist Party.

Moreover, why should Beijing be so worried about a few million Tibetans yearning for independence when the armies of China are millions strong and its 1.35 billion people almost entirely united in steadfast opposition to succession? And surely a state as mighty as China should be able to withstand the loss of the Tibetans and their desolate mountain plateau with air so thin headaches are a sure thing for most lowlanders?

Of course the issue of indepedence for Tibet is coloured by issues of greater import to China then simply independence.

Strategically, Beijing worries arch-rival India might strike up an alliance with independent Tibet against China. Or worse, Lhasa might be open to foreign powers, like America or India, establishing military bases in Tibet. China seeks to defend its borders by ensuring its neighbours are friendly and not playing host to foreign militaries. America's presence in Afghanistan, Kyrgyzstan, South Korea and Japan is worry enough. Nevermind Washington's close ties with New Delhi, Taipei and perhaps one day, Hanoi.

Economically, Tibet may turn out to be a treasure trove of minerals and perhaps given recent finds of gas in neighbouring Sichuan province even energy. If Tibet does turn out to sit atop rich seams of ore and lakes of oil and gas it would ease Beijing's dependence on faraway Africa to supply the booming economy which is powering China's (so far) peaceful rise to supremacy in Asia.

Politically, Beijing fears the loss of Tibet would be to pull a loose thread on a woollen jersey which would see Xinjiang, which was once East Turkestan of the Uyghurs until invaded by the imperial armies of the Qing dynasty in Beijing a few hundred years ago, make a bid for indepedendence and perhaps even Inner Mongolia. And even greater concern is Taiwan, the island off China's eastern coast where the majority consider themselves citizens of Taiwan not China, which Beijing insists is a territory of China which will be subdued by force should it opt for independence. In Taiwan it is common to see stickers and posters expressing solidarity with Tibet.

But would the thread stop unravelling there? History suggests otherwise. Dynasties rose and fell for five thousand years, some ruled far into Central Asia, others only the Han heartlands on the plains. Guangdong (Han) and Guangxi (Zhuang), for example, only fell under the imperial Mandate of Heaven's direct control a few hundred years ago. Yunnan (only half Han) and East Turkestan broke free for a few decades in the early 20th century when the imperial yoke evaporated. And if one looks back over history, ever since Shi Huangdi united the Han lands, successors have struggled to impose their writ only to eventually fail.

Succession by parts of China not historically Han, whom comprise 91.9 percent of the citizens of China, could set a precedent for other parts of the country unhappy with the distribution of power and Beijing's rule. And for provincial or regional elites yearning to be their own boss, independence may have an attraction beyond ethnic solidarity and the glory of China whipped up by the communist party.

China's weakness, politically, is that the path to the top is not open to competition. So for some regional cadres their aspirations for the top job have only the slimmest of chances. In the absence of meaningful, open competition for those jobs, such as through elections, an alternative is to run your own state.

The signs are already there. Beijing's impotence is regularly put on display when provinces ignore its edicts, acts of disobedience which would have been unthinkable when communist ideology was strong. In March, China Times reported interviews with young people in Shanghai in which they said they cared not if Tibet and Taiwan left China. Such views are not entirely uncommon among young, urban Chinese exposed to ideas and thoughts from beyond China, especially those who have travelled widely or studied overseas. Nevertheless they do remain a small minority in a niche.

The greatest threat then of revolt in Tibet is the questions it raises about what exactly is China?

With the stark differences in spoken language, diet, customs and even animosity found around the country, it's not hard to notice the cracks. One China as imposed by the party apparatchiks is a concept akin to saying there can only be One Europe, instead of many states which share some aspects of cultural and historical heritage considered to be European and associate freely in patterns of their own through mutual agreement, but which remain free to express their differences. The communist party is trying to defend an idea of China as a nation state with a Chinese identity and citizenship fashioned from the rubble and subjects of an imperial empire which claimed legitimacy as the defender and promoter of the culture and civilisation of the Han.

This act of nation-building is far from complete. The spectre of Han domination often pokes through the idea of Chineseness. Most strikingly in the state's repeated broadcasts of Tibetans attacking Han in Lhasa and elsewhere. One interpretation is that these broadcasts were intended to project the idea that the Han were under threat and should therefore rally together and unite behind the party. But in the information age can the party control the interpretation of the message? How will ordinary Han interpret these events? Through the party line of printed propaganda parroted by television newscasters? Or will they make up their own interpretations through the thousand-words of a picture? Can Beijing control such interpretations or will they come to control Beijing?

In 2005 propaganda helped whip up anti-Japanese sentiments which quickly snowballed into mass protests which tested Beijing's control. Pressure was eased by the police busing protestors to the Japanese embassy in Beijing where they could vent their anger in a few minutes of egg-throwing before being bussed away. Nationalism is a two-way street between the state and society. Backing down in international disputes may not be an acceptable policy for a public gripped by nationalism even if Beijing knows it would be the less costly policy.

The communist party has nevertheless sought legitimacy by grasping the nettle of nationalism, as the ideology of communism fades, its mission now to defend and promote all things Chinese. This requires that citizens, from whom in the absence of direct, open, free and fair elections the party can only claim passive legitimacy, believe and accept that the only possible political idea for the lands they call home is the state of China. Resistance in Tibet, Xinjiang, Inner Mongolia and Taiwan question that idea. So too the disobedience of the provinces.

Why should the communist party be any more successful at binding the lands it now rules together than its equally authoritarian predecessors the emperors? China's leaders are surely not blind to the fates of states imposed and melded by autocracy which have broken up in the face of reawakening of ethnic or regional identities in recent times such as the Soviet Union and Yugoslavia.

Their collapse came as a surprise principally because the idea of systemic change was considered a fantasy, something not worthy of serious consideration or research. But what if analysts had bothered to seriously think the unthinkable, entertain the fantastical, simply to look? Great social change is like a tsunami, largely unseen, a faint ripple passing in a blink yet with the capacity unleash massive force when its momentum encounters the right environment as it did in eastern Europe in 1989. The fantastical is worth considering for no other reason than its ability to shatter the status quo.

China's leaders were supposedly spooked not only by communism's downfall in eastern Europe and the Soviet Union, but by their very own brush with failure when demonstrations rocked Beijing in the summer of 1989. Those events in which thousands were slaughtered left a deep scar upon society and another black mark in the party's report card. Summer in Beijing and spring in Tibet are linked by their shared revolt against autocracy. Indeed almost every one of the tens of thousands of protests in China each year is in its own way a protest, among other things, against the autocracy which permits so much abuse to take place because the state and the party are largely above the law and suffused with the arrogance of those whose power seems beyond challenge.

Yet their reaction to protests in Beijing in 1989, to the Falungong meditation movement, and now revolt in Tibet indicates a niggling fear. They should be worried. A severe recession has yet to uniformly test China since the good times started rolling after economic reform began in 1979. Could the communist party, could China survive a perfect storm of mass protests by the unemployed and hungry and by enthnic successionists? With inflation gripping the world, food seemingly running short, and recessions looming in China's key export markets, a test may come sooner than we think. Revolt in Tibet then matters to Beijing because it is a revolt against the very idea of China.