Among these principles the main one lays down that as all men are alike by race and nature, so in like manner all are equal in the control of their lives; that each one is so far his own master as to be in no sense under the rule of any other individual; that each is free to think on every subject just as he may choose, and to do whatever he may like to do; that no man has any right to rule over other men. In a society grounded upon such maxims all government is nothing more nor less than the will of the people, and the people, being under the power of itself alone, is alone its own ruler. It does choose, nevertheless, some to whose charge it may commit itself, but in such wise that it makes over to them not the right so much as the business of governing, to be exercised, however, in its name.
The authority of God is passed over in silence, just as if there were no God; or as if He cared nothing for human society; or as if men, whether in their individual capacity or bound together in social relations, owed nothing to God; or as if there could be a government of which the whole origin and power and authority did not reside in God Himself. Thus, as is evident, a State becomes nothing but a multitude which is its own master and ruler. And since the people is declared to contain within itself the spring-head of all rights and of all power, it follows that the State does not consider itself bound by any kind of duty toward God. Moreover, it believes that it is not obliged to make public profession of any religion; or to inquire which of the very many religions is the only one true; or to prefer one religion to all the rest; or to show to any form of religion special favour; but, on the contrary, is bound to grant equal rights to every creed, so that public order may not be disturbed by any particular form of religious belief. —from Immortale Dei (1885)