I am basing my answer to this question on Robert Bellah’s article entitled “Civil Religion in America.” The version I am using, found in the link below, was published in 1967, but was based on something written the year before. In this article, Bellah is arguing that there is a civil religion that is referred to often in American political discourse. This civil religion has aspects of Christianity, but it is not really Christian. Instead, it is centered around the idea of America as a country that is specially situated to fulfill the will of God.
The first main aspect of Bellah’s argument is his definition of America’s civic religion. He explicitly says that he is not claiming that we worship our country. Instead, he says that the vast majority of Americans (again, remember that he is writing over 40 years ago) believe in “a set of beliefs, symbols, and rituals that I am calling American civil religion.”
The next argument that Bellah makes is that this civil religion came from the ideas of the Founding Fathers. The Founding Fathers did not typically make reference to Jesus Christ or to Christianity even at a time when practically every American was Christian. Instead, they talked about God. They did not talk about any particular theological conception of God, just about the idea that there was a God who controlled the universe and who had a certain set of goals that he wanted America and Americans to pursue. Bellah argues that the civil religion of this time was somewhat more of an Old Testament religion. As mentioned before, it referred to a unitary God, not to the Trinity. Bellah goes on to say that the God of that civil religion was “also on the austere side, much more related to order, law, and right than to salvation and love.”
At that time, the main idea of the civil religion was that America was a chosen country. In this way, America was seen as similar to Israel, which had been God’s chosen country in the Old Testament. God had chosen America to do his will in the world.
With the Civil War, Bellah says, the civil religion changed to some degree. It became somewhat more of a New Testament religion. The civil religion did not change and become more explicitly Christian (though we might argue that it has done this since Bellah wrote), but it came to emphasize the idea of sacrifice for the country. Just as Jesus sacrificed for all people, there were many Americans who were said to have sacrificed their lives for the country. Honoring them became a large part of the civil religion. This aspect of the civil religion began with the Gettysburg Address and continued with the way in which people saw Lincoln’s own death. It continued with the veneration of the dead in the secular holiday of Memorial Day. We can argue that this aspect of the civil religion has only been strengthened now as we honor the dead of 9/11 and as we are more vocal in paying our respects to the war dead on days like Veteran’s Day.