19 When you started your crusade, it was said that your efforts would be of short duration and that the effects would not be lasting because, as the vigilance of Bishops and faithful gradually diminished, the producers would be free to return again to their former methods. It is not difficult to understand why certain of these might be desirous of going back to the sinister themes which pander to base desires and which you had proscribed. While the representation of subjects of real artistic value and the portrayal of the vicissitudes of human virtue require intellectual effort, toil, ability, and at times considerable outlay of money, it is often relatively easy to attract a certain type of person and certain classes of people to a theatre which presents picture plays calculated to inflame the passions and to arouse the lower instincts latent in the human heart.
Source: Vigilanti Cura (Vatican.va)