The sentencing of China's two leading dissidents to lengthy prison terms is a clear sign that the government's unusual tolerance of attempts in recent months to form an opposition political party is at an end.

Xu Wenli and Wang Youcai were key figures of the China Democracy Party, which the court described as an illegal organisation. Another prominent member of the party, Qin Yongmin, has also been tried and is awaiting a verdict.

Given the government's consistent opposition to organised dissent, it's not surprising that the first ever attempt to form and register an opposition party has resulted in lengthy jail terms for the group's leaders. What's more surprising is that the government waited so long before clamping down.

Many observers believe China may have felt restrained by a series of important diplomatic events this year, including visits by President Clinton and the United Nations Human Rights Commissioner Mary Robinson.

Attempts to reassert control

But there remains a key difference between this crackdown and some of the others that the government has launched against political dissent during the last two decades of reform.

During the 1980s and early 1990s, such crackdowns were usually combined with attempts to curb liberalisation in other spheres, particularly culture and the economy. They were also often accompanied by signs of conflict between reformers and conservatives within the Communist Party.

The reason for this is that party hard-liners would seize the opportunity of a crackdown on dissent to press their case for a more sweeping reassertion of party control. They would argue that the emergence of political dissent was an inevitable consequence of relaxation in other spheres.

Punk lives on

In more recent years, however, these hard-liners have become more marginalised. Now the prevailing view in the party leadership appears to be that while dissidents pose a potentially serious challenge to party control, those engaged in, say, avant garde art or punk rock provide a relatively harmless outlet for frustrated youth.

Some Chinese intellectuals called what was until recently the more relaxed political atmosphere in China a new Beijing Spring.

In some respects the dissidents' trials signal that this Spring is now over. But it's less certain that the authorities will follow through with a crackdown on publishers, who this year have produced dozens of books exploring issues which once have been considered taboo.