IT is the role of the police to enforce the law, not to make it or lobby China to change it. The police management's toughly-worded rebuke of Local Inspectors' Association chairman Robert Chau Chuen-kung for attempting to enlist the help of the Preliminary Working Committee (PWC) in reviving capital punishment was therefore harsh but wholly appropriate. Although Mr Chau had not yet taken the case directly to the China-appointed body, his position and the public manner of the announcement made a formal approach almost unnecessary. There can be no doubt that the PWC has registered his remarks or that some of its members will be ready to make capital out of any hint of police dissatisfaction at government policy. Calls for the re-introduction of the death penalty are precisely the kind of populist gambit which the unrepresentative PWC will seize on to give it some semblance of political legitimacy. It is, of course, the right of any politician or elected official to make an approach to China's ''second stove''. Public servants, however, particularly the police, have a duty to remain neutral and apolitical. They have no right to undermine the legitimacy of the Legislative Council by querying its decisions with the PWC or any other outside body. The public trusts the police to act impartially and apolitically to uphold Hong Kong laws. If officers of Mr Chau's standing begin to align themselves politically with China then confidence will be irretrievably undermined. Who will trust the police to remain impartial after 1997, if they cannot do so today?