Mostly, filmmakers complain that they must work against muddled or moving boundaries. And parents' groups grouse about 'ratings creep,' a perceived tendency for a category like PG-13 to permit ever more violence, sex and profanity over the years to reach impressionable youth. Yet it was Mr. Valenti's genius to have devised an apparatus that is not bound by precedent, changes its definitions at will and, ultimately, serves the motion picture industry by becoming, at any given moment, as permissive or restrictive as the prevailing climate seems to demand... for nearly 40 years, Mr. Valenti's raters have largely kept politicians and busybodies out of the film business, even if that meant playing somewhat unpredictable busybodies themselves. They haven't always been fair, and not entirely pleasant to deal with. But in the end, theirs was no mean achievement.

Film·Politics·Ratings·Censorship·Flexibility