Inherit the Wind (1960)
Spencer Tracy as Henry Drummond: Can’t you understand? That if you take a law like evolution and you make it a crime to teach it in the public schools, tomorrow you can make it a crime to teach it in the private schools? And tomorrow you may make it a crime to read about it. And soon you may ban books and newspapers. And then you may turn Catholic against Protestant, and Protestant against Protestant, and try to foist your own religion upon the mind of man. If you can do one, you can do the other. Because fanaticism and ignorance is forever busy, and needs feeding. And soon, your Honor, with banners flying and with drums beating we’ll be marching backward, BACKWARD, through the glorious ages of that Sixteenth Century when bigots burned the man who dared bring enlightenment and intelligence to the human mind!