The First Amendment to the U.S. Constitution is pretty simple. It was meant to be.
Just read it:
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.
Notice, the Bill of Rights is a guarantee of freedom, and the first freedom protected - before the freedom of speech or press, by the way - is freedom of religion. The First Amendment was meant to secure liberty, including liberty of religion. The point: The non-establishment clause was meant to promote religious freedom, not restrict it.
Some people think this clause was written to protect atheists and restrict religion. It wasn't. It was written to protect religious people and promote their liberty in the public square.
There is no separation of church and state in the Constitution. Let me repeat: There is no separation of church and state in the Constitution. The Constitutional language is "non-establishment," not separation. There’s a difference.
When people ask me, "Don’t you believe in separation of church and state?" I say, "No. And neither should you. Instead, I believe in the Bill of Rights."
So next time the question of separation of church and state arises – whether in regard to a cross on a hilltop in San Diego, or “under God” in the Pledge of Allegiance—remember what the First Amendment of the Constitution actually says and what its first clause was designed to do: protect and promote religious freedom.