BY China's standards, former Beijing mayor Chen Xitong got off lightly. Sixteen years in prison for corruption and dereliction of duty might seem harsh in Hong Kong terms, but it is light for the mainland, compared with sentences meted out to lowlier criminals and for lesser crimes. Chen may be released within five years. That, certainly, has been enough to anger the dissident groups who regard him as one of those responsible for the 1989 Beijing massacre, as well as those who believe he deserved a tougher sentence for abusing his position. Should a man be allowed a minimal sentence, just because he has powerful friends? Others may argue the trial and the sentence show China has understood the rule of law means the law must apply fairly to all. They might say that the evidence cited against the former Beijing party chief warranted the sentence he received, but hardly more. It was not as if the mansions where he wined and dined so lavishly were his own. He might have overspent massively on building and furnishing them, but they were built as government property. And the bribes lined up as evidence, though too many to be dismissed as trivial, are individually small beer. Such arguments should be treated with care. A single trial, held in closed court, proves nothing about possible changes in the mainland judicial system. It certainly does not prove the most powerful in the land are no longer above the law. It shows nothing except that Chen is now out of favour politically. The relatively lenient sentence cannot even be held to prove conclusively that Chen still has connections powerful enough to save him. It might equally reflect a fear of setting precedents. In a system which uses the courts to purge its opponents, a victim's enemies must know the tables can be turned. In a system without transparency, a closed trial with a well-publicised sentence, or a public show-trial for that matter, can never be more than a one-off performance. If the sentence was meant to be exemplary, and show that top leaders cannot escape the law, it missed its target. For the courts to be taken seriously, there have to be standards. These must be openly acknowledged, codified and applied to everyone equally. Trials must be open and judicial decisions seen to be just and predictable. China still has some way to go before the rule of law is seen to apply.