HAROLD AND MAUDE: Key.

"Harold and Maude," released in 1972, has become a "cult film," which is the movie-land term for a motion picture whose popularity lasts longer than its original promotion campaign.

The audience for a cult film is generally composed of people who have already seen the picture. If they still like it, and, in addition, find a new perspective for enjoying it, it may have a chance of reaching the next step, which, in extravagant movie language, is "film classic." That simply means that, like "Gone With the Wind," "Fantasia" or "Casablanca," the picture has acquired a second-generation audience.

"Harold and Maude," at the age of six, does not seem likely to make it. The shock of its grisly humor still works, but the shock of its philosophy is gone. Its anti-materialistic, anti-militaristic, pro-human, free-expression stand has been so thoroughly preempted by the society in these few years that proclaiming that "there are a million ways" for "you to be you" sounds like a cosmetic advertisement or the slogan of a bank "for people."

Harold, played by a marvelously deadpan Bud Cort, it a poor little rich boy; Maude, in the way Ruth Gordon always plays the spry, is an elderly eccentric. Together they fight the authority figures. To make this attractive, there has to be a collegiate '60s assumption that spontaneity is more important than law. You have to find it charming that Maude steals automobiles for fun (not profit) and unsporting of the police to attempt to arrest her.

You must accept the validity of their fighting Harold's social mother and his military uncle.But it's difficult now to accept such stock figures as an officer who shouts "Kill! Kill! Kill!" in conversation, and a woman who's interested only in her coiffure. Even as comic stereotypes, they have both been toppled.

And you must feel that Harold and Maude have come up with something valid of their own to offer. Maude's assertions that she doesn't have a driver's license "because I don't believe in licenses"; that she doesn't pray to God - "I communicate"; that the best thing is "to reach out, take a chance, get hurt even"; and that "people are my species" are such cliches today that it's difficult to believe they could have passed for the call of freedom only six years ago.