ADOPTING populist causes can be attractive to political (and policy) leaders. Attractive, but often wrong. The Attorney-General, Jeremy Mathews, is to be commended for rejecting a call by Legislative Councillor Lau Wong-fat for a minimum sentence for manslaughter. Mr Lau's implication that manslaughter is always a crime so heinous it must be punished with greater severity than, say, robbery without violence, is false. It is based on a misunderstanding of the difference between murder and manslaughter. While the former presumes an intention to kill - however fleeting the impulse - manslaughter assumes the killing was unintentional. Not all manslaughter is innocent of criminal intent. The death may result from cruel and deliberate battery of the victim and in many cases the lesser charge of manslaughter is brought only because the intention to kill is impossible to prove. In such cases, the maximum penalty of life imprisonment is justified, as it is for murder. But, as Mr Mathews pointed out, there are many cases of manslaughter where no serious misconduct was intended, where a push - or even a punch - can have unexpectedly fatal consequences. In others, the killer may claim diminished responsibility and require hospital treatment. In such cases the element of vengeance implicit in longer sentences (and in populist calls for them) is not appropriate. However, there is room for the legal system to tailor sentences more specifically to individual cases. One way to do this would be to set sentences which mean what they say. If a man is sentenced to five to 10 years in prison, he should not be entitled to remissions until five years have passed. The public should be confident that a man will serve the sentence the courts decide his crime deserves.