The US Catholic bishops started the Legion of Decency in the early 1930’s when the modern movie industry had taken off. They worked with movie studios to create a voluntary production code. It was actually a huge help to the movie business as it made movies acceptable to mainstream America in a way they had not been previously.
There had been a code for movies in the 1920s and 1930s. This code was very loose to begin with, with lots of wiggle room. For instance, a wife and mother could ditch her family, enjoy all kinds of pleasures and cruelty for 60 minutes, then in the last 30 seconds say, Gosh I should not have done all that. Right.
In the early 1930s Catholic laymen joined with the bishops, and mobilized huge numbers of people to boycott movies, even picket theaters. This brought about in 1934 a new production code, with a new chief, Joe Breen who was trained by and relied on Jesuit advisers. This new code drastically changed the way Hollywood did business. They would demand advance copies of the scripts, insist on changes before the scenes were even shot.
The code dominated only American made movies, but the Legion in the early years threatened to boycott and picket any theater, permanently, that showed films they condemned - so foreign films that were objectionable had limited showings in the US at specialty theaters… The Legion was a little stricter than the Production Code administration, but mostly coincided. The Production Code was drastically watered down by the late 1960s.
The Legion faded out after Vatican II. It is important to recognize it because it was an example of lay activity, in union with the bishops,** before Vatican II. ** I have read too many articles and too many adult ed classes that start out saying how before Vatican II the laity were passive, but that since V II we are supposedly more active, empowered.
This is utter nonsense.