IT IS A venerable legal maxim that hard cases make bad laws. So it happened in Watergate: the hard, indeed the aberrant, case of Watergate made the bad law of the independent-counsel statute, first enacted as Title VI of the Ethics in Government Act of 1978 and twice reauthorized during the eighties. Scheduled by its own terms to expire in 1992, the statute, which applies only to certain high-ranking members of the executive branch, deserves to go gentle into that good night reserved for bad legislation.