I think it’s commonly understood that the ideals framing the Declaration of Independence were the result of the Enlightenment Age and Protestant notions, which were somewhat at odds with Catholic political thought. However, there’s an interesting lecture at http://www.udallasnews.com/media/paper743/news/2005/10/12/News/Guest.Lecturer.Reminds.Of.Americas.Catholic.Roots-1016918.shtml by Scott McDermott of Vanderbilt University who points to John Carroll, one of the signers of the Declaration, as an introducer of Catholic thought to the new colonial government.

McDermott explained that before the Reformation, common law was understood to be based on natural law. St. Thomas taught that if a law ‘conflicts with the law of nature it will no longer be law but rather a perversion of law.’ He and others also held that when a ruler becomes a tyrant and forces his citizens to act contrary to natural law he abdicates his sovereignty and sovereignty reverts to the people who must then delegate a new sovereign.

The lecturer says that such Catholic ideals were “unwittingly” brought to the Colonial mindset. He goes on to say,

“The culmination of the American rediscovery of natural law and natural rights is, of course, Jefferson’s Declaration of Independence, with its appeal to the “Laws of Nature and of Nature’s God,” and its listing of the self-evident natural rights to justify resistance to tyranny,” McDermott said. “Anglo-American republican liberalism embraced the natural law, not the general will, as its liberating principle.”

I think this is interesting and points to something rather telling in modern times. Democracy without regard for such “natural rights” is not what the Founders envisioned, and yet seems to be precisely what the United States is leaning towards.