Activist Tan Zuoren was tried in a court in Chengdu yesterday for subversion over criticism of the June 4, 1989 crackdown in Tiananmen Square. There seems little doubt, however, that the catalyst for his detention in March was his refusal to abandon his high-profile investigation of the part official corruption and incompetence played in the collapse of shoddily built schools in last year's Sichuan earthquake, in which more than 5,000 children died. It's probably true, as the indictment states, that Tan seriously damaged the image of the Communist Party and the government in statements after the quake. But then, so did the National Audit Office, which found that embezzlement by rural officials of funds for school construction was rife, forcing schools to run on 55 per cent of their budgets. The conduct of proceedings did little to improve the government's image. The trial was over quickly, without the defence being allowed to call its witnesses and show supporting video evidence. Officials barred parents of quake victims from the court. Leading artist and rights activist Ai Weiwei was beaten up by Chengdu police before he was due to appear as a defence witness and Hong Kong media representatives were physically harassed. Sadly, there is nothing unusual in all this. It is part of a pattern of stifling dissent ahead of the 60th anniversary of the People's Republic of China, when the authorities are striving to maintain the appearance of social harmony. In this case, the authorities could have delayed the trial to a less sensitive time, leaving Tan incommunicado in detention. In the event, it has backfired on China's image. The whole affair is a reflection of the extent to which the notion of a harmonious society based on the rule of law is still at odds with the ideological view of the judiciary as an instrument of the state. Courts still function as instruments of political control, rather than as independent, impartial adjudicators. Tan's experience is mirrored, so far, by that of four employees of Anglo-Australian mining firm Rio Tinto detained five weeks ago and yesterday formally arrested over commercial espionage. What sets that case apart is that one of them is an Australian citizen. As a result, the absence of even the rudiments of his legal right in Australia - or for that matter Hong Kong - to a fair opportunity to defend himself has sparked bilateral tension and international attention. Tan's presence in the dock raises the question of the jurisdiction and autonomy of the courts. The people who should have been on trial are those he tried to bring to account for corruption and incompetence. Yet party leaders resisted efforts by the families of child quake victims and their lawyers to seek justice in the courts. Beijing has shown awareness of the problems in the justice system but little urgency. The authorities should strive to fast track specific steps towards more judicial autonomy first proposed four years ago by the Supreme People's Court, and implement a draft law conferring basic rights and protection on both lawyer and client, such as confidential interviews. The intimidation and obstruction of defence lawyers by law enforcement officers remains one of the biggest blots on the mainland's justice system. The best way of securing social harmony is for the mainland to develop a fair, transparent and effective means of resolving disputes. That requires a legal system which fully respects the right to a fair trial. Sadly, Tan's case shows there is a still a very long way to go.