The Free Exercise Clause[1] accompanies the Establishment Clause of the First Amendment to the United States Constitution. The Establishment Clause and the Free Exercise Clause together read:
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof...
Free exercise is the liberty of persons to reach, hold, practice and change beliefs freely according to the dictates of conscience. The Free Exercise Clause prohibits government interference with religious belief and, within limits, religious practice.[2] To accept any creed or the practice of any form of worship cannot be compelled by laws, because, as stated by the Supreme Court in Braunfeld v. Brown, the freedom to hold religious beliefs and opinions is absolute.[3] Federal or state legislation cannot therefore make it a crime to hold any religious belief or opinion due to the Free Exercise Clause.[3] Legislation by the United States or any constituent state of the United States which forces anyone to embrace any religious belief or to say or believe anything in conflict with his religious tenets is also barred by the Free Exercise Clause.[3]
In 1878, the Supreme Court was first called to interpret the extent of the Free Exercise Clause in Reynolds v. United States, as related to the prosecution of polygamy under federal law. The Supreme Court upheld Reynolds' conviction for bigamy, deciding that to do otherwise would provide constitutional protection for a gamut of religious beliefs, including those as extreme as human sacrifice. The Court said: "Congress cannot pass a law for the government of the Territory which shall prohibit the free exercise of religion. The first amendment to the Constitution expressly forbids such legislation."[4] Of federal territorial laws, the Court said: "Laws are made for the government of actions, and while they cannot interfere with mere religious beliefs and opinions, they may with practices."[4]
Jehovah's Witnesses were often the target of such restriction. Several cases involving the Witnesses gave the Court the opportunity to rule on the application of the Free Exercise Clause. Subsequently, the Warren Court adopted an expansive view of the clause, the "compelling interest" doctrine (whereby a state must show a compelling interest in restricting religion-related activities), but later decisions have reduced the scope of this interpretation.