This is not an auspicious year for the Chinese Communist party, which is having to confront two anniversaries it would rather remain forgotten. The first, the 50th anniversary of the failed uprising in Tibet, passed without incident this week, if we are to believe the Chinese premier. Wen Jiabao said at his annual press conference yesterday that the peacefulness of Tibet was proof that his policies were correct. The second, the 20th anniversary of the Tiananmen Square massacre, is fast approaching. Both present the government with real political difficulties.

A year after the anti-Han riots in Lhasa, the capital of Tibet, in which 19 people were killed, the peace of the region can be measured in more than one way: Tibetan regions across western China have been flooded with troops. About 220 Tibetans were killed, 7,000 detained, and more than 1,000 are still missing in the crackdown which followed the riots, according to the Tibetan government in exile. There have been spontaneous if isolated flare-ups since, but the single most significant collective act of protest was the boycott of the Tibetan new year in February, despite generous official inducements to throw wild parties. Tibetan officials blamed the increased Chinese military and police activity on "intensified secessionist activists". Whomever you believe, peace is the last word that springs to mind in the Tibet Autonomous Region.

The Dalai Lama described life in the land he fled 50 years ago as "hell on earth" in an uncharacteristically angry denunciation of Chinese policy this week. But he did not abandon the "middle way" - the commitment to maintain a dialogue that Beijing shows no interest in continuing. And he has repeatedly said he is not seeking independence. Chinese bloggers have locked swords over whether Tibet is historically part of China, and whether Tibet has benefited from the enormous amount of Chinese investment which has modernised a backward nation. But neither going back to what happened in the Tang, Song and Ming dynasties nor the investment that the central government has poured in will change the central grievance burning away in the hearts of six million Tibetans - the sense that their culture and identity are under threat.

As that identity is being buried under tons of concrete and glass at home, so it is being sustained by the diaspora abroad. The two processes work in inverse proportion to each other. So the conflict is set to persist no matter how quickly Lhasa becomes a Chinese city. It will outlive the changing relationship between China and the US. Tibet is China's problem and it will not be airbrushed away.