IN A TRULY bipartisan and quintessentially presidential gesture, Ronald Reagan the other day announced that he was not going to let his aides keep leaking things to the press any more. Party's over, boys. Henceforward, anyone who wants to communicate with the press will get clearance first from the office of David Gergen, White House director of communications. Otherwise, a small number of White House officials designated to do the talking to reporters--office of Pressblab?--will be the sole official spokesmen.

Want to bet? Don't misunderstand us. We are not issuing a threat here, or even a challenge, so much as we are expressing our skepticism on this subject, which is both invincible and profound. This is because, going back to President Kennedy, anyway, these foredoomed "henceforwards" have been issuing forth: only in the presence of a third person, only with the specific permission of higher-ups, only if a full report of what went on is made later. It all has the ring of those restrictions people attempt to impose on the dating practices of their 14-year-olds, and normally it proves to be just about as successful.

There are reasons for this. The most important of them is that the people who really want to put out information with their own particular spin on it just keep on doing so, regulations or not. Nothing stops them. The ones who get stopped are those a president or departmental secretary or other top official could usually use on the press chitchat circuit. What a president does with this kind of decree generally is to intimidate his best and most loyal background spokesmen and explainers and leave the field to the malevolent and the axe-grinders.

Some of the reaction to the president's newly announced plan has been very dramatic and even hysterical. We think what Mr. Reagan is doing is foolish and that its results, if any, will not be those he has in mind. But, to put it mildly, we really don't see the Eastern European police state that has been invoked as the proper analogy. Comparisons should be made instead to the efforts of the Carter and Nixon and Johnson and Kennedy administrations to assert absolute control over the government-press exchanges of their time, dismal failures all. We have too much confidence in the maddening persistence and ingenuity of reporters, especially under challenges such as this, to be professionally fearful that canned news will become the norm. What Mr. Reagan is probably doing is benching some of his own most persuasive and plausible defenders.