More mayoral hysteria.

This time Rudolph Giuliani, who has only a passing acquaintance with the First Amendment, is determined to protect us from some nasty pictures at an exhibition. And if the only way to do that is to cripple a terrific cultural resource like the Brooklyn Museum of Art -- well, that's a price the Mayor is perfectly willing to pay.

He's already gone after the porn parlors. Now it's a museum. Maybe he can find some nasty passages in some raunchy books and close a few libraries.

You don't think there's a chill in the air? Listen to this courageous statement of support for artistic freedom put out separately by the directors of the Metropolitan Museum of Art and the Museum of Modern Art:

"I understand that the Brooklyn Museum and the office of the Mayor are in a dialogue. Anything I might say could compromise those talks."

With all due respect to the respective directors, Philippe de Montebello and Glenn D. Lowry, a mugging is not a dialogue.

The Mayor, of course, has little to lose. How do you lose when one of the pictures in question is a collage that purports to show the Blessed Virgin spattered with elephant dung? This exhibition was made to order for the Mayor's tyrannical, puritanical and political tendencies.

It's a no-brainer for him. And that's the problem. For hizzoner, it's as if there were no larger principle involved.

In London in the latter part of the 16th century, a law was passed that barred the production of plays that did not have the approval of the mayor and the aldermen. The author Victor L. Cahn has written: "In reaction to this ordinance, playhouses were built just outside municipal limits and consequently beyond the realm of jurisdiction, and here professional actors and playwrights truly thrived."

One of the playwrights was a fellow named Shakespeare. The Mayor would have loved it. Try to imagine Mr. Giuliani with the power to approve Shakespeare's plays. I've no doubt the Bard would have high-tailed it to New Jersey.

In 1940 the philosopher Bertrand Russell was offered a professorship at the City College of New York. The puritans went wild. It was understood that Lord Russell favored the notion of men and women having sex, even unmarried men and women.

This caused normally mild hearts to thump and strong men to grow faint. According to Russell's biographer, Ronald W. Clark, one outraged New Yorker wrote to Mayor Fiorello La Guardia: "Quicksands threaten! The snake is in the grass! The worm is busy in the mind!"

The writer begged the Mayor for help: "I beg Your Honour to protect our youth from the baneful influence of him of the poisoned pen -- an ape of genius, the devil's minister of men."

Mayor La Guardia, a hero to Mayor Giuliani, was happy to oblige. A clownish judge blocked the appointment when a lawsuit was filed that described Russell as "lecherous, libidinous, lustful, venerous, erotomaniac, aphrodisiac," etc. La Guardia promptly cut off funding for the professorship and forbade city lawyers to appeal the judge's ruling.

La Guardia's action was disgraceful and one of his top aides, Charles Culp Burlingham, did not try to hide his dismay. Thomas Kessner, in his biography of La Guardia, wrote:

"As usual Burlingham put it best: 'Why should a man with your record in a free country do to the CCNY what the Nazis have done to Heidelberg and Bonn? . . . Your attempts to dispose of the case while it was in the courts was bad enough; but to prevent the Board of Higher Education appealing to higher courts is far worse. It is not like you.' "

Artistic freedom? Intellectual freedom? These are terms empty of meaning to some politicians. Mayor Giuliani appears to enjoy the chilling effect he has on artistic and intellectual enterprises. He likes to exhibit his raw, naked power.

John Cardinal O'Connor and the Catholic League are understandably upset over the exhibition planned by the Brooklyn Museum. And a healthy portion of the Mayor's support comes from Catholic voters. And Mr. Giuliani is no doubt personally offended by some of the works to be displayed.

That's enough for this Mayor to come to the conclusion that a museum should be brought to its knees.

There is no larger principle.