I think Grapes of Wrath may be the most liberal movie of all time or maybe the most influential liberal movie. Certainly for its time it was way out of the mainstream and I believe it won best picture?
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I have to concur about it being one of the most influential over the lang haul.
That's where I learned that faith in G-d, hard work, and intestinal fortitude were not nearly enough to sustain a family in America. You will never truly be free to lead a life of dignity until the government takes you in and protects you from all those cruel capitalist animals that are just waiting to destroy your life.
That's the lesson we children were supposed to learn from that so called "classic" American novel. It was a few years before I began to see that trash for what it really is, classic communist propaganda. It's a good thing public school comes to an end just in time to be able to think for yourself, or I'd be doomed to a leftist anti-American mindset my entire life.