The Chinese government insists that next summer's Olympic Games are not political. A senior official said as much again on Thursday.

Yang Chunlin has cause to disagree.

Mr. Yang, a social activist arrested recently for distributing a petition titled "We Don't Want the Olympic Games, We Want Human Rights," goes on trial next week, charged with the eminently political crime of "inciting subversion of state power." He faces up to five years in jail.

Politics has burst onto the Olympic scene front and center – complicating Beijing's plans for a trouble-free coming-out party in August – with Steven Spielberg's resignation this week as artistic adviser to the Beijing games in protest of China's Darfur policy.

Mr. Spielberg accused Beijing of not putting enough pressure on its ally, the Sudanese government, to help end the humanitarian crisis in Darfur. "My conscience will not allow me to continue with business as usual," he said in a statement.

Chinese Foreign Ministry spokesman Liu Jianchao responded Thursday that "linking political issues with the Olympic Games is not in line with the Olympic spirit."

Despite Chinese officials' insistence that political issues should not interfere in this year's Olympic Games, it is unsurprising that they have. Within China, a one-party state, almost every aspect of society is politicized. Abroad, many activist groups object to one aspect or another of Chinese government policy.

"China is particularly vulnerable and particularly politically sensitive" to outside criticism, says David Zweig, head of the Center for China's Transnational Relations at Hong Kong University of Science and Technology.

"They do lots of things the world does not particularly like, and they are very sensitive to what the world thinks," Professor Zweig adds. "They have made it to world-class status and they are getting dumped on."

As foreign critics of Chinese policy on a range of issues – from Taiwanese independence to Tibet and from Darfur to press freedoms – gear up to use the Olympic Games as leverage in their campaigns, Beijing is handicapped by its lack of skills in handling dissenters. At home, they have simply suppressed them.

Officials say they are ready to deal with political opponents. "We have heard voices from all sides," said Jiang Xiaoyu, vice president of the Beijing Olympic Games Organizing Committee (BOCOG) last year. "[There] will be more and more of these kinds of voices and maybe more resonant. We are mentally prepared."

But it took the Foreign Ministry two days to respond to Spielberg's bombshell, suggesting a low level of readiness.

"The government was intellectually aware" of the likelihood of political problems surrounding the games, says Sidney Rittenberg, a China expert who knows the country's top leaders personally. "But I don't think they had real flesh-and-blood understanding of it. The gathering storm will come as a bit of a shock."

Politics have intruded on many past Games, starting in 1906, when an Irish medal winner climbed the flagpole to tear down the British flag that had been raised in his honor, in the days before Irish independence.

The 1936 games in Nazi-ruled Berlin are often seen as the nadir of attempts by the host nation to use the festivities for political gain. African nations boycotted the 1976 Games, the US and some of its allies boycotted the 1980 Moscow Games to protest the Soviet invasion of Afghanistan, and the Soviet Union and its satellites boycotted the 1984 Games in Los Angeles in revenge.

For nearly 25 years, however, in Seoul, South Korea; Barcelona, Spain; Atlanta, Sydney, Australia; and Athens; the Olympics have been mostly free of political trouble. "It is possible to proceed without controversy," says David Wallechinsky, an Olympic historian. "Nobody was mad at the Greeks. They haven't offended anybody."

Beijing, however, is making its Games a powerful symbol of China's emergence as a world power, "and that, by its very nature, is political," says Zweig.

Some officials have acknowledged as much. "It is not only an international sports event, but also a very important political mission," stated a 2006 opinion article in the People's Daily. "It is not only an Olympic feast for the Chinese people, it can also arouse Chinese patriotism."

An awareness of how much the Games mean to China, and a fear of upsetting the authorities, appear to have been behind a plan by the British Olympic Association, revealed last weekend, to make British athletes sign a contract pledging not to comment on "politically sensitive issues" in Beijing.

In the wake of an uproar, the BOA says it will reword the contract to conform to the Olympic charter, which says: "No kind of demonstration or political, religious, or racial propaganda is permitted in any Olympic sites, venues or other areas." It does not forbid athletes from expressing opinions elsewhere.

Other groups are less worried about riling the Chinese. "If the Games show China emerging as a world power, it's fair to raise questions about their complicity in Darfur," says Allyn Brooks-LaSure, spokesman for the Save Darfur Coalition. He adds that "As soon as we started talking about the Olympic Games, there was at least a response from the Chinese. It is clear they are hearing what we are saying."

Campaigners on other issues, such as Tibetan rights, human rights abuses, and religious persecution, are gearing up to use the Olympics as a stick with which to beat Beijing, but the government issued them a stern warning two weeks ago.

"Those who always look at China through dark glasses have produced a sort of baffling excitement," an editorial in the People's Daily declared. Activists who say that "they can exert enough pressure to force China into a position where it cannot help but act according to their wishes … have clearly miscalculated."

Others are not so sure. International pressure "might make some difference" says Mr. Rittenberg. "Those in the leadership who are sensitive to these issues feel strengthened."

Still, he says, "the net result is more negative than positive," given how proud most ordinary Chinese are that their country is hosting the Games. "Indignation at Spielberg is going to be almost universal.

"If the games are substantially damaged" by any snowball effect from Spielberg's resignation, Rittenberg warns, "that is going to cause immense resentment among ordinary Chinese at what they see as unjust foreign interference."

For Darfur advocates, the ball is in China's court. "We will continue pushing till there's a response from China that makes a difference" says Mr. Brooks-LaSure. "The Chinese are going to see and hear a crescendo of activism as the games get closer."

"Beijing is going to have to start thinking how to react well and intelligently" to such pressure, says Zweig. "They are going to be confronting this kind of thing all the time."