Some right-wing Christians like to say that the US is a Christian nation. The atheist and moderate response to this is usually to cite the Founding Fathers, some of whom made uncomplimentary remarks about Christianity. But there is another sense in which the US is, unquestionably, a Christian nation: the Discovery Doctrine.

When the European gained the ability to mount ocean-faring voyages of discovery/conquest, the question rapidly arose of the legal status of the lands they found. Of course there were already people inconveniently living in those lands, but the Europeans didn't let these trivialities interfere with their desire to own everything. In 1452, Pope Nicholas V issued the bull called Romanus Pontifex, declaring war against all non-Christians throughout the world, and specifically sanctioning and promoting the conquest, colonization, and exploitation of non-Christian nations and their territories.

Over subsequent generations, this became established law: The first Christian expedition to "discover" a territory became the legal title-holder to that territory under European law (which, given that Europe enjoyed absolute military supremacy, rapidly became the only law that mattered). The people already living there became subjects of the discovering monarch, retaining the right of occupancy but subject to whatever duties, taxes and so forth their new king imposed.

This was the legal basis by which the British, French and Spanish settled and conquered North America. In 1823, the United States Supreme Court formally recognized this policy in Johnson v. M'Intosh, calling it the Discovery Doctrine. Several subsequent Supreme Court decisions (notably Cherokee Nation v. Georgia, Oliphant v. Suquamish Indian Tribe and Duro v. Reina) referred to this doctrine.

The Discovery Doctrine is the legal basis by which the land of Native American tribes could be taken and punitive "treaties" imposed and then ignored. Without this doctrine, the United States would promptly cease to exist, since there is no other justification for most of the states' claims of territorial sovereignty within their own borders. So it remains on the books to this day.

So in the end, the United States is and will remain a Christian nation - though perhaps not in a way that Fox News would wish to discuss.