"You know, there are some words I've known since I was a schoolboy: ' With the first link, the chain is forged. The first speech censured, the first thought forbidden, the first freedom denied, chains us all irrevocably.' Those words were uttered by Judge Aaron Satie as wisdom and warning. The first time any man's freedom is trodden on we're all damaged."

From Star Trek: The Next Generation episode "The Drumhead".

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http://www.youtube.com/watch?feature=player_embedded&v=jkXtf_FZKbA