I'm glad I'm not the one in China. Politics always invades the Olympics. Undoubtedly, the 2008 Olympics will capture the public imagination for a couple of weeks, and then be summarily forgotten. Let's not forget that this a communist nation which is not that friendly to the United States. BEIJING -- A 2006 Winter Olympics U.S. athlete who is a prominent critic of China's links to Sudan said his visa to attend the Beijing Games was revoked, while a pro-Tibet group said four of its activists were detained outside the main venue for the Games.Less than 24 hours before he was to fly to Beijing, Joey Cheek was called by an official from the Chinese Embassy in Washington and told that he couldn't go, he said. The official said he was "not required to give a reason" for revoking visas, Mr. Cheek said.Mr. Cheek, a 29-year-old gold-medal-winning speed skater in 2006, wasn't going to compete in Beijing but had planned to attend in order to draw attention to genocide in Darfur, which critics say Beijing abets through its ties to the Sudan government. His organization, Team Darfur, urges athletes to support peace in Darfur.Separately, a group called Students for a Free Tibet said four British and American activists were detained Wednesday in Beijing after unfurling Tibetan flags and two large banners outside the "Bird's Nest" stadium to protest Beijing's policies in the territory. The activists were detained by Chinese authorities, the group said.State media confirmed the stadium arrests.In response to questions about Mr. Cheek, China's foreign ministry said in a statement that the nation "made appropriate arrangements" for visas during the Games, and aims "to provide a comfortable, safe environment for the watching and playing of games." It added that visa issuance is a "sovereign thing, according to China's law and practices of host countries of previous Olympic Games and other big international sports events."China's foreign minister said in the spring that any attempts to link the Olympics to Darfur go "against