You ought to be true for the sake of the folks who think you are true. You never should stoop to a deed that your folks think you would not do. If you are false to yourself, be the blemish but small, you have injured your folks; you have been false to them all.
The dissident does not operate in the realm of genuine power at all. He is not seeking power. He has no desire for office and does not gather votes. He does not attempt to charm the public, he offers nothing and promises nothing. He can offer, if anything, only his own skin -- and he offers it solely because he has no other way of affirming the truth he stands for. His actions simply articulate his dignity as a citizen, regardless of the cost.
Great is truth, but still greater, from a practical point of view, is silence about truth. By simply not mentioning certain subjects... totalitarian propagandists have influenced opinion much more effectively than they could have by the most eloquent denunciations.