Under this surreal 'rule by law', Ai Weiwei is guilty

When the Chinese foreign ministry spokesman Hong Lei insisted to reporters in Beijing this week that "China is a country ruled by law", and "other countries have no right to interfere" in the case of the detained avant-garde artist Ai Weiwei, there was a certain truth to his remarks. China is a country ruled by law. But this is quite different, as many victims of official corruption in China have discovered, from being a country in which the rule of law prevails.

The rule of law contains important principles: the law is supreme, and all have equal rights before it. The concept of rule by law was pioneered by one of China's harshest imperial regimes, the shortlived but influential Qin dynasty, 2,000 years ago. The Qin emperor saw the law as an instrument of authoritarian rule, to be defined and used as he chose, and it is this tradition that appeals to the current Chinese leadership.

Without understanding the distinction it is hard to see how China's growing body of law, with its court apparatus, judges and lawyers, really functions. Under a conventional system the supreme judicial authorities might be expected to have some legal background, but in China the head of the political and legal committee of the central committee of the Communist party, Luo Gan, is an engineer turned security supremo who is there to ensure the system serves the party. As he has put it, his role is to guard against "negative western legal concepts" like judicial independence.

The party controls the courts, appoints the judges and routinely dictates the verdicts. Even if a citizen wins a case, the court has little power to enforce the verdict without the backing of those same state officials. A Chinese litigant is often in the Kafkaesque situation of being dependent on those who committed the abuse for redress.

Nevertheless, with few other possibilities, growing numbers of Chinese citizens try to use the law to fight back against corruption. But if the citizen is expected to obey the law, the party state itself can shape and deploy it to suppress dissent and to preserve the careers of corrupt party officials. The party's discipline department will act against deviant officials when it wishes, but such matters are too important to be the concern of the legal system.

The law is, however, a handy means of detaining, harassing and disbarring defence lawyers who get in the way of the state, and for the prosecution of complaining citizens for ill-defined offences against public order, social stability, national security or, as in Ai Weiwei's case, economic crimes.

Ai's alleged economic crimes are bound to pale in comparison with those of state officials, who are reckoned to steal more than $80bn a year. A report by Beijing's Renmin University in 2005 estimated that 90% of Chinese officials spend more than they nominally earn, so if Ai's economic crimes do exist, they are unlikely to be the real problem.

Far more important are his stubborn efforts to document the names of those killed by official corruption. In this he has enjoyed more latitude than many: as the son of the celebrated revolutionary poet Ai Qing, he counts as one of China's new aristocracy. But when he set out to collect the names of the children who perished in the deathtraps of their badly-built schools in the 2008 Sichuan earthquake, he was treading on sensitive toes.

No official has been prosecuted for the corruption that produced those schools. Instead, the parents of the dead children have been harassed; a teacher who tried to help them has been jailed; and Ai Weiwei himself has suffered a brain haemorrhage from a beating last year in Sichuan. When 58 migrant workers died in a fire in a corruptly-built Shanghai tower block, Ai again set out to document the dead. This is not listed as a crime under Chinese law, but it certainly annoys those responsible.

Ai was not the first to test the limits of official tolerance. When corruption in the dairy industry led to the poisoning of a quarter of a million babies in 2008, the news was suppressed for several months so as not to spoil the Olympic mood. The firm responsible was prosecuted, but many complicit officials were not. Among the parents who remained vocally unhappy was Zhao Lianhai, who continued to campaign for compensation for his infant son, who developed kidney stones. He was sentenced to two-and-a-half years in jail. Another father, Guo Li, got a five-year sentence.

But punishing the victims for taking legal action against corrupt officials no longer seems to be enough. In recent months a series of detentions and disappearances of active lawyers has signalled a more robust attack on the exercise of legal rights. The most notorious case is that of Gao Zhisheng, a leading human rights lawyer who was given a three-year suspended sentence in 2006 for "inciting subversion" – and who disappeared last April.