Does the Constitution Require a "Wall of Separation" Between Religion and Government?

The phrase "wall of separation" is not in the Constitution. It comes from a letter written by Thomas Jefferson to the Danbury Baptist Association, in which Jefferson congratulates the Baptists, and by implication all Christians, and people in other religions, on their ability to freely run for office, and participate in all governmental activities in the United States. Host Martin Tanner provides many proofs that religion was not prohibited, but encouraged in the U.S. government. Examples: The Supreme Court in several opinions said the U.S. is a Christian Nation. Congress always opens and closes sessions with a prayer. Benjamin Franklin wanted the Bible to be a textbook in public schools.