"If there is any fixed star in our constitutional constellation, it is that no official, high or petty, can prescribe what shall be orthodox in politics, nationalism, religion, or other matters of opinion or force citizens to confess by word or act their faith therein."

Quoting from West Virginia State Board of Education v. Barnette, 319 U.S. 624, 63 S.Ct. 1178 (June 14, 1943) at 642.