FIRST, A WORD about families and guidelines concerning their conduct. Chances are good that most American families already have such guidelines. These mostly promulgate rules governing such exasperating questions as the acceptable decibel level for audio appliances during certain hours, whether and when the offspring will pick up their far-flung effects and the assignment and performance of custodial duties for maintaining the family's quarters.

But have you thought of how hard it would be to distribut family guidelines of the sort that Jimmy Carter has just issued -- guidelines meant to instruct others, in this case the whole mighty federal bureaucracy, in the details of how they are to treat members of your family? Mr. Carter's new memo arises from an evident intent to de-Billify his presidency and his reelection campaign, and it is an awkward, even tortured exercise. Imagine the deliberations, for instance, that went into deciding the degree of consanguinity that would be regarded as marking an individual as a member of the president's family for purposes of the guidelines. Siblings? Yes. Cousins? No. Ex-spouses? Hmm.

Behind the starchy lines of the president's warning to federal bureaucrats not to let themselves be exploited by members of his family is a failure to grasp a self-evident fact: that the problem does not arise from the bureaucracy's vulnerabilities or even from his relatives' indiscretions. It arises precisely from his own conception of his family as an extension of his official self, as a legitimate and appropriate instrument of governing, which is just all wrong in our democratic system. It makes a kind of quasi-royal family out of the president's kin.

Thus did the president himself commit the basic mistake by using his brother Billy -- as he had previously used his wife and his mother and his sister and his son -- to perform missions that he the president insisted were not ceremonial but substantive. Billy Carter, of course, was dispatched on a delicate mission involving the hostages in Iran. This was wrong, and still the president does not realize it. Indeed, he compounds his error, in his new memo, by singling out a category of contacts in which a family member, having been called upon by the president "to act as his official representative at a ceremony, function, or meeting in the United States or abroad," should be accorded "the courtesies and amenities appropriate to his or her official status and to the occasion -- no more, no less." Is that not tempting the possibility of descending again into the very swamp from which he is trying to extricate himself? What he needs to issue is not a memo to the bureaucracy but a vow to himself: Keep the family at home.