The 1st Amendment to the Constitution states, “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof.” Through its free exercise clause, the 1st Amendment protects the individual's right to freedom of conscience and free expression of religious beliefs.
See also Religious issues under the Constitution
The Oxford Guide to the United States Government. Copyright © 1993, 1994, 1998, 2001, 2002 by John J. Patrick, Richard M. Pious, Donald M. Ritchie. All rights reserved.