YOU COULD hear it said last week that the law that led William Bennett to withdraw before he could even be installed as Republican national chairman is proof of the sticky over-regulation of federal ethics, a live example of a straitjacket that keeps too many able people from federal office. Not so; not even Mr. Bennett says he thinks so.

The law, which was sharpened but not fundamentally changed last year, says basically that senior officials who leave the government have to wait a year before returning as lobbyists. The device is anything but perfect, but the cooling-off period does help to keep recently departed officials from using their still-live connections to exercise undue influence over the public business for private gain, both their own and clients'.

Mr. Bennett had just resigned as director of national drug control policy when asked to become Republican party chairman. He said yes, but on condition that he could also maintain an extensive private speaking schedule for honoraria; in part to pay back a six-figure advance on an unwritten book, he needed the money.

The problem was that he then risked being hired to speak by groups whose public-policy positions he could subsequently find himself advancing inside the White House as party chairman. The connection might be entirely innocent. He might be advocating a position he had long held; he might have been asked to speak precisely because he had long held it and in no way to induce him to do so. It would nonetheless look bad, likely hobble Mr. Bennett in both sets of activities and sometimes take him uncomfortably close to the line in the law even if not beyond it. His own brother, currently counsel to the Senate Ethics Committee in its investigation of the Keating Five, advised him so -- that he couldn't speak for hire and serve as chairman at the same time without possible conflicts, or at least their appearance -- and he gave up the chairmanship.

The point is made that other party chairman have had outside interests and not had to give them up; the current Democratic chairman Ron Brown continues to have a connection with a lobbying law firm here. That's so, but these are problems, insofar as problems arise, for the parties and their chairmen, independent of what the rule should be for former ranking federal employees. Mr. Bennett was free to go on the speaking circuit or become party chairman, but for a year he couldn't easily do both. That's a fair price for putting a reasonable moat around the government; he was right to choose.