The hope that there may some day be an end to TV advertising aimed at kids is slowly extinguishing itself. In remotest theory, the Federal Trade Commission has the power to put commercials aimed at small children off the air, but that this power ever will be translated into facts grows less and less likely in the months of dispute on this billion-dollar subject.

In this case, the Villain isn't a craven-hearted, softly corrupt federal trade commissioner listening to exparte whispers of the special interests. No, this time the cause will be lost because the principal official actor has been too candid, too forthright and too honest in public demeanor to feign a dishonesty he can't truthfully claim.

Michael Pertschuk, the FTC's new chairman and one of President Carter's most distinguished appointments, has been ordered to absent himself from the deliberations on kidvid advertising by a federal judge. The judge, Gerhard A. Gesell, is that rarity among the tribe of black robes, a widely respected and honored man, so what we have here isn't hanky-panky, but a system which knows how to checkmate itself when it needs to.

Acting on a suit filed by the Association of National Advertisers, the American Association of Advertising Agencies and other worthy trade associations, the judge ruled that Pertschuk can't take part because he has prejudged the case: "Going far beyond general observations of policy and tentative statements of attitude, the chairman has by his use of conclusory statements of fact, his emotional use of derogatory terms and characterizations, and his affirmative effort to propagate his settled views made his further participation improper."

In effect, Gesell has said it's okay for a member of a federal commission to make "general observations of policy," and it's okay for him to make "tentative statements of attitude," but he can't go too far in expressing his opinion before the formal commission deliberations and ruling. How far is too far? You'll never know until a judge tells you you've gone too far.

It is by inventing such entirely subjective distinctions that judges maintain the confusion which attends so much public business. There is no a priori way in the world that a government official can know when he is uttering an innocent "tentative statement" and when he is bespeaking a fatal "conclusory statement of fact."

The Federal Trade Commission in its unsuccessful defense of its independence from an overly active judiciary maintained that commission rulemaking is a form of legislation. In other words, the commissioners are not under any more of an obligation to strike judicially impartial poses than a senator is.

The irony is that Pertschuk was appointed by the president and confirmed by the Senate because he stands for things like banning ads from kidvid. The president sent him over to FTC to do exactly the kind of job that he was attempting to do when th judge jumped in. If the commission, led by its outspoken chairman, had been allowed to go ahead and promulgate an illegal rule, a rule that offended some law or constitutional principle, there would have been time enough for that mess of advertising agencies to go beseeching justice from our judicial friend.

How we ever are going to get kiddies' commercials off the air escapes imagining. Another commissioner, Robert Pitofsky, has disqualified himself because prior to his appointment, he had represented one of the public-interest groups that asked the commission to protect the children in the first place.

In a few years those who fail to appreciate how very limited the powers of the presidential office can sometimes be will be blaming President Carter for not acting to help the weakest and most innocent of our society. And the toddlers will continue defenseless against the art, money, psychological marketing warfare and greedy chicanery of those who make their living, like the vile coachman in Pinocchio, teaching small persons to love the sugar which will one day rot their teeth out.