In response to an individual who used the founding of the United States to justify opposing gay marriage:
Well I would expect you to at least give me one example as to why [the right to marry established in Supreme Court cases overturning interracial marriage laws] doesn't apply to gay marriage, or to recall your statement that marriage is a "privilege" but I suppose that would be too much to ask:
And don't justify your religious agenda by using "this nation was founded on theistic religious belief." This is the most overused, and misrepresented argument uttered by conservatives in defense of injecting religion and legislating morality in public policy. No, this nation was not founded on "theistic religious belief" and let me elaborate;
Firstly, many of our Founding Fathers were deists or anti-clerical, but most importantly they were children of the Enlightenment, believing in empiricism and the worth of scientific endeavors to support a seemingly naturalistic world view. This isn't to say they were all deists, some were religious, one being John Jay who believed that Christians are best fit to serve this country, but does not represent a public policy position. For that, you have to look at the ideas that were behind the Founding Documents.
Thomas Jefferson, the author of the Declaration of Independence, was vehemently opposed to religion. In his letters to Adams, he talks of the religious superstitions of Christianity as "one day being amongst the likes of Jupiter and other false gods." He authored the Jefferson Bible, where he rewrote the New Testament taking out the supernatural, believing strongly in the ethical teachings of Jesus but denying his divinity. Jefferson was the first to note and advocate the "wall between church and state" of the Founding Fathers, initially used by the founder of Rhode Island Baptist Roger Williams. He demonstrated his support of this separation in public policy as well apart from his private letters, writing the Virginia Statute for Religious Freedom, which would become the basis for the First Amendment and the Free Exercise Clause in the Constitution.
James Madison, the author of the Constitution, has expressed in countless letters his original secular intent of the government, calling for the "perfect separation between the ecclesiastical and civil matters" in a letter he wrote to Edward Livingston in 1822. He even expressed opposition to Congressional chaplains and days of prayer.
George Washington was arguably a deist, or at least a nonreligious man, although not expressing it in public, but rather his personal letters. He refused to take Holy Communion on Sundays. Benjamin Franklin was a deist, denouncing religion in many of his writings; "The way to see by Faith is to shut the eye of Reason." John Adams expressed doubts, especially in his writings to Jefferson. And Thomas Paine was perhaps the most outspoken of them all, completely denouncing religion and despising it in his book "The Age of Reason" and his other writings.
Also you should note, the Constitution makes no mention of "Jesus Christ, divinity, Bible, Creator, Divine, or God." And the Declaration of Independence, although mentioning the rights "endowed by our Creator," this does not make it explicitly Christian, it was simply the reiteration of a Lockean concept that Jefferson elaborated on.
And lastly one of the most important pieces of evidence for the secular intent of the United States is the Treaty of Tripoli signed in 1797. "As the Government of the United States of America is not, in any sense, founded on the Christian religion" is the direct quote from it, and was passed unanimously in the Senate, being read out loud on the Senate floor and copies being passed out for each Senator to read. There were no objections, because the secular intentions were clear, no matter how religious these Senators were they agreed on this basic concept of separation because they feared religion in politics would be destructive in the United States, as it had been in Great Britain. It was even published in the Pennsylvania Gazette with no public backlash. Although this treaty is now defunct, it makes the position of the Founding Fathers quite clear; that we were to be seen as a secular nation throughout the world, that we do not profess any particular faith, and that we are a nation that allows all different creeds none of which would ever hold an advantage or special privilege in the rule of law.
I hope that clears everything up for you, and I hope you also realize that even if all of this nation was Christian that would not make the United States a Christian nation. We are, at least our original intent was, to be a secular republic that does not succumb to mob rule of the majority; where the rights of the peoples are protected, and this includes their right of religion or belief not to be infringed by the legislating power of another. It was a pure product of the intellectual followers of the Enlightenment, and its importance cannot be understated.
The War of 1812 was a brutal conflict between the infantile United States and the British Empire, and the culmination of years of unsettled dues from the Revolutionary War. The first real test of power since its independence, aside from the Barnaby Wars, the United States was faced with a dilemma; they lacked the proper ground troops to deal with such an impending crisis from the British Crown. Scrambling for solutions, then-president James Madison sought advice from his Secretary of State James Monroe who then pitched in his two cents -- instate a national draft of 40,000 men. It was this proposal that Senator Daniel Webster fiercely criticized on the House floor in his December address during the winter of 1815. His words are perhaps one of the most eloquent defenses I have read against conscription, against tyranny, and for liberty. Here's some food for thought: 
