High Noon 1952

You can read this one either as an allegory of US foreign policy post WWII (The US is the sheriff who has been protecting everyone for years but has been abandoned and must stand his ground against a new enemy) or an allegory of McCarthyism, proposing that Hollywood needed to pull together and stand up for it's blacklisted writers instead of allowing McCarthy and his witch hunt to pick them off one by one. Seeing as writer Carl Foreman was one such blacklisted writer, High Noon is probably the later allegory concealed as the more acceptable former.