Alexis de Tocqueville: Democracy In America, vol 1

Men are not corrupted by the exercise of power or debased by the habit of obedience, but by the exercise of a power which they believe to be illegal and by obedience to a rule which they consider to be usurped and oppressive.

It is natural that they should hasten to invoke the assistance of religion, for they must know that liberty cannot be established without morality, nor morality without faith; but they have seen religion in the ranks of their adversaries, and they inquire no further; some of them attack it openly, and the remainder are afraid to defend it.