This is an excerpt from the book THE SECRET TERRORIST by Bill Hughes which sheds some light on the differences between the Roman Catholic Church beliefs and the Constitution of the United States of America. This particular statement came from Charles Chiniquy, a Catholic priest, who was later put on trial for a crime he didn't commit and was defended by our very own, President Abraham Lincoln. For more on the story you can read chapter 4 of the book which is available online.
Liberty of conscience is proclaimed by the United States a most sacred principle, which every citizen must uphold.... But liberty of conscience is declared by all the popes and councils of Rome, a most godless, unholy, and diabolical thing, which every good Catholic must abhor and destroy at any cost. — Charles Chiniquy, Fifty Years in the Church of Rome, Chick Publications, page 284.
Long before I was ordained a priest, I knew that my church was the most implacable enemy of this republic. My professors… had been unanimous in telling me that the principles and laws of the Church of Rome were absolutely antagonistic to the principles which are the foundations stones of the Constitution of the United States of America. — Charles Chiniquy, Fifty Years in the Church of Rome, Chick Publications, p. 283.
Watch carefully as Chiniquy compares the distinctions between the two.
1st. The most sacred principle of the United States Constitution is the equality of every citizen before the law. But the fundamental principle of the Church of Rome is the denial of that equality.
2nd. Liberty of conscience is proclaimed by the United States, a most sacred principle which every citizen must uphold, even at the price of his blood. But liberty of conscience is declared by all the popes and councils of Rome, a most godless, unholy, and diabolical thing, which every good Catholic must abhor and destroy at any cost.
3rd. The American Constitution assures the absolute independence of the civil from the ecclesiastical or church power; but the Church of Rome declares that such independence is an impiety and revolt against God.
4th. The American Constitution leaves every man free to serve God according to the dictates of his conscience; but the Church of Rome declares that no man has ever had such a right, and that the pope alone can know and say what man must believe and do.
5th. The Constitution of the United States denies the right for anybody to punish any other for differing from him in religion; but the Church of Rome says that she has the right to punish with the confiscation of their goods, or the penalty of death, those who differ in faith from the pope.
6th. The United States have established schools all over their immense territories, where they invite the peoples to send their children, that they may cultivate their intelligence and become good and useful citizens. But the Church of Rome has publicly cursed all those schools, and forbidden their children to attend them, under pain of excommunication in this world and damnation in the next.
7th. The Constitution of the United States is based on the principle that the people are the primary source of all civil power. But hundreds of times, the Church of Rome has proclaimed that this principle is impious and heretical. She says that all government must rest upon the foundation of the Catholic faith; with the pope alone as the legitimate and infallible source and interpreter of the law. — Ibid. p. 284.