Today I stumbled upon Federalist Paper #51, one of the 85 Federalist Papers written (mostly) by Alexander Hamilton and James Madison. The Federalist Papers were written shortly after the Constitutional Convention of 1787, to bolster support for the new Constitution among the public. Paper 51 was authored by Madison, who was also the primary author of the Bill of Rights.
It is of great importance in a republic not only to guard the society against the oppression of its rulers, but to guard one part of the society against the injustice of the other part. Different interests necessarily exist in different classes of citizens. If a majority be united by a common interest, the rights of the minority will be insecure. There are but two methods of providing against this evil: the one by creating a will in the community independent of the majority -- that is, of the society itself; the other, by comprehending in the society so many separate descriptions of citizens as will render an unjust combination of a majority of the whole very improbable, if not impracticable.
Here Madison warns against the tyranny of the majority, which might (he postulates) usurp the rights of the minority. Madison warns that any such usurpation would be, in his word, evil.
He sees two ways to prevent this evil: one by authoritarian rule; and one by social diversity. Care to guess which of these Madison prefers?
The second method will be exemplified in the federal republic of the United States. Whilst all authority in it will be derived from and dependent on the society, the society itself will be broken into so many parts, interests, and classes of citizens, that the rights of individuals, or of the minority, will be in little danger from interested combinations of the majority. In a free government the security for civil rights must be the same as that for religious rights. It consists in the one case in the multiplicity of interests, and in the other in the multiplicity of sects.
In other words: if we are a Christian nation, that's not what Madison had in mind. He saw the United States as a quilt, not a blanket. In fact, he saw that the United States could only exist as a quilt. And Madison foresaw Glenn Beck style demagogues too, in FP #10; once again, diversity was the bulwark to defend against it.
The influence of factious leaders may kindle a flame within their particular States, but will be unable to spread a general conflagration through the other States. A religious sect may degenerate into a political faction in a part of the Confederacy; but the variety of sects dispersed over the entire face of it must secure the national councils against any danger from that source.
Let me close with this quote, which needs to be more widely read:
In a society under the forms of which the stronger faction can readily unite and oppress the weaker, anarchy may as truly be said to reign