Aaron Morrison is a very bright New Jersey lad who happens to be an activist in the Ku Klux Klan. Though he has completed his courses with straight A's, Holy Spirit High School is withholding his diploma. He is suing, with the aid of the American Civil Liberties Union.

It all started three years ago when Aaron witnessed a debate between the Rev. Jesse Jackson and David Duke, the Klan's imperial wizard. (Is a wizard higher than a dragon? I can never keep these things straight.) Not exactly a dialectical match-up to remind one of Socrates versus Thrasymachus, but it was enough for Aaron. He gave the verdict to the wizard and joined the Klan.

Last August, to the mortification of his liberal parents, Aaron held a Klan rally on the front lawn of his home. Shortly afterward, his school's principal, the Rev. Thomas Plaoude, notified him that he wouldn't be receiving his diploma.

Dr. and Mrs. Morrison loyally support their son: "Aaron has the right to his own principles and convictions. We've always encouraged him to think for himself." Of course, they add, they would have "preferred" his joining the Repulicans or Democrats.

But what do they mean? The Morrisons have allowed their son to join the Ku Klux Klan. That looks rather like a dereliction on their part. They have allowed a Klan rally to occur on their private property, thereby setting a mark for tolerance rivaled by Leonard Bernstein. One hopes Mrs. Morrison stopped short of serving hors d'oeuvres.

G.K. Chesterton noted that an open mind, like an open mouth, should be open for the purpose of closing on something. Yes, we all want our children to do their own thinking. We also want them to be able to do their own math. But we also want them to be able to get the right answers. When they err grievously, we do them no favor by indulging them. How seriously can parents be taking their own "principles and convictions" when they can only say they would have "preferred" Democrats to Klansmen?

Aaron has evidently been taught to "think for himself" by people who have never learned to think for themselves. If they had, they wouldn't use that slovenly phrase, which has come to mean not so much thinking independently as thinking irresponsibly. Joining the Klan isn't an exercise in pure cognition; it is participation in an enterprise whose achievements range from consistent bad taste to occasional murder. Aaron has brought disgrace on himself and his family; his school is trying to point this out and dissociate itself from the scandal.

That is where the ACLU comes in. ACLU lawyer Jerry Kay explains: "We're not defending the content of the Klan's philosophy; we're defending freedom of speech. The Constitution's a good thing. Let's keep it intact."

Yes, let's. The First Amendment reads: "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech . . ." Aaron's freedom of speech is not at issue. Neither Congress nor any state agency threatens it, and only they can violate it. The point of the First Amendment is precisely, by removing state sanctions against speech, to allow private persons and agencies to impose their own sanctions. Owners of baseball teams routinely fire Billy Martin for the things he says, and nobody thinks the Constitution has been put to the torch.

A private, religious organization has at least the same rights as the New York Yankees (who, by the way, play in a tax-funded stadium). What the ACLU is doing in the name of keeping the Constitution intact, is demanding that the state tell a religious body how to conduct its business even when it attempts to take a moral position.

"Civil liberties"? George Orwell would be amused. The ACLU's "civil liberties" are really state-imposed standards, and its victories have generally increased centralized state power. Gnawing away at the independence of private institutions is no way to expand personal freedom.