The way to combat noxious ideas is with other ideas. The way to combat falsehoods is with truth.

We need to be bold and adventurous in our thinking in order to survive.

As nightfall does not come all at once, neither does oppression. In both instances, there is a twilight when everything remains seemingly unchanged. And it is in such twilight that we all must be most aware of change in the air – however slight – lest we become unwitting victims of the darkness.

The struggle is always between the individual and his sacred right to express himself and the power structure that seeks conformity, suppression, and obedience.

The liberties of none are safe unless the liberties of all are protected.

http://en.wikiquote.org/wiki/William_O._Douglas