The favorite complaint of candidates in Election '88 has been the mournful cry, "They've changed the rules." "They" means the press, and "the rules" refers to their willingness to delve into all the nooks and crannies of a candidate's personal life.

The unspoken assumption here is that the press sets the rules. The truth is that candidates can also shape the rules, if they have the guts to do it.

It is true that this pre-election year has seen some alteration in the rules of the game from previous campaigns. Extramarital affairs, unattributed quotes and collegiate marijuana indulgences have not traditionally been among the decisive issues around which presidential elections revolved. That they have become prominent says something about the aggressiveness of the media -- and a lot about the passivity of the candidates.

The press is at its most self-righteous in asserting its prerogatives to ask everything about anything. Its defense is that it asks personal questions of the candidates because of the public's right to know. That, however, begs the questions: who gave the press the right to decide what is the public's right to know?

Certainly the candidates themselves have a right to an opinion on the answer to this question. No one gave the press an exclusive right to determine what people need to know. Nor does the press have any corner on the market in deciding the correct balance between this right and other equally critical rights, such as the constitutional one to privacy.

The candidates for our highest office are not just choir boys waiting for instructions from the holy airwaves on the tune they're supposed to hum. Candidates ought to decide what in their personal backgrounds is necessary for the public to know, put it out in their official campaign material and leave it at that. At the same time they should understand that if they are hiding something important it will eventually come out.

If the candidates are confident that they have leveled with the public, they should then be confident enough to tell the press to "Get Stuffed." These candidates can help define the rules by acting presidential. They can do this, to borrow a phrase, by Just Saying No.

When a reporter asks whether a candidate will discuss his wife's alleged abortion or whether he has ever been unfaithful . . . just say, No.

When another media maven inquires whether a candidate has ever drunk too much, or tried the wrong drug, or whether his family has, just say, No, I won't discuss it.

The press will continue to ask these questions if the candidates continue to answer. If the candidates don't answer, and stick to it, the questions will eventually stop.

So come on, guys. Show some guts. Demonstrate a little backbone. Don't answer personal questions anymore. Who knows, it might be a way of illustrating some presidential quality -- like leadership.

Who's first?

The writer, a political consultant, was national campaign manager for the Mondale-Ferraro campaign.