First Amendment

"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances."

Detroit Free Press: Carve First Amendment in some stone

"The United States is not a Christian nation. It seems sensible to begin there, since it's the crux of the dispute.

Yes, the men who invented the nation were mostly Christians. Yes, too, Christianity is the nation's majority religion.

But the point is, this is not a theocracy, not a nation where the rulings of holy men carry official weight. The Framers made that impossible when they wrote a First Amendment forbidding the government from endorsing any religion..."