We have seen how the First Amendment to the Constitution says absolutely nothing about keeping religion out of government. But there are still those (Catholics included) who insist that religious liberty requires an absolute or strict separation of state and church. Is this the teaching of Vatican II? In a word, no. In its Declaration on Religious Freedom (Dignitatis Humanae) Vatican II said:
"Since the common welfare of society consists in the entirety of those conditions of social life under which men enjoy the possibility of achieving their own perfection in a certain fullness of measure and also with some relative ease, it chiefly consists in the protection of the rights, and in the performance of the duties, of the human person. Therefore the care of the right to religious freedom devolves upon the whole citizenry, upon social groups, upon government, and upon the Church and other religious communities, in virtue of the duty of all toward the common welfare, and in the manner proper to each.
The protection and promotion of the inviolable rights of man ranks among the essential duties of government. Therefore government is to assume the safeguard of the religious freedom of all its citizens, in an effective manner, by just laws and by other appropriate means.
Government is also to help create conditions favorable to the fostering of religious life, in order that the people may be truly enabled to exercise their religious rights and to fulfill their religious duties, and also in order that society itself may profit by the moral qualities of justice and peace which have their origin in men's faithfulness to God and to His holy will.
If, in view of peculiar circumstances obtaining among peoples, special civil recognition is given to one religious community in the constitutional order of society, it is at the same time imperative that the right of all citizens and religious communities to religious freedom should be recognized and made effective in practice.
Finally, government is to see to it that equality of citizens before the law, which is itself an element of the common good, is never violated, whether openly or covertly, for religious reasons. Nor is there to be discrimination among citizens.
It follows that a wrong is done when government imposes upon its people, by force or fear or other means, the profession or repudiation of any religion, or when it hinders men from joining or leaving a religious community. All the more is it a violation of the will of God and of the sacred rights of the person and the family of nations when force is brought to bear in any way in order to destroy or repress religion, either in the whole of mankind or in a particular country or in a definite community." (DH, No. 6).