The United States Constitution contains several provisions that limit the role of religion in government and protect the freedom of religion for individuals. The First Amendment to the Constitution states that "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof." This is known as the Establishment Clause and the Free Exercise Clause. The Establishment Clause prohibits the government from establishing or endorsing a national religion, while the Free Exercise Clause ensures that individuals have the right to practice their own religion freely without government interference.
Additionally, the 14th Amendment to the Constitution extends the protection of the Bill of Rights, including the First Amendment, to state and local government as well.