Primary Source: Reynolds v. United States (1879)

Reynolds was decided in a time of westward expansion and the growth of the Mormon Church, particularly in Utah. The question raised was whether sincere religious beliefs exempted a practicing member of the Mormon Church from the laws against polygamy. The case was the first time the Supreme Court addressed the meaning of free exercise of religion. The Court also expressed its view that civil society may legitimately regulate marriage, which it argued was the foundation of social relations.

. . . . [T]he question is raised, whether religious belief can be accepted as a justification of an overt act made criminal by the law of the land. The inquiry is not as to the power of Congress to prescribe criminal laws for the Territories, but as to the guilt of one who knowingly violates a law which has been properly enacted, if he entertains a religious belief that the law is wrong.

Congress cannot pass a law for the government of the Territories which shall prohibit the free exercise of religion. The first amendment to the Constitution expressly forbids such legislation. Religious freedom is guaranteed everywhere throughout the United States, so far as congressional interference is concerned. The question to be determined is, whether the law now under consideration comes within this prohibition. . . .

Polygamy has always been odious among the northern and western nations of Europe . . . . At common law, the second marriage was always void, and from the earliest history of England polygamy has been treated as an offence against society. . . .

Marriage, while from its very nature a sacred obligation, is nevertheless, in most civilized nations, a civil contract, and usually regulated by law. Upon it society may be said to be built, and out of its fruits spring social relations and social obligations and duties, with which government is necessarily required to deal. In fact, according as monogamous or polygamous marriages are allowed, do we find the principles on which the government of the people, to a greater or less extent, rests. . . .

[T]he only question which remains is, whether those who make polygamy a part of their religion are excepted from the operation of the statute. If they are, then those who do not make polygamy a part of their religious belief may be found guilty and punished, while those who do, must be acquitted and go free. This would be introducing a new element into criminal law. Laws are made for the government of actions, and while they cannot interfere with mere religious belief and opinions, they may with practices. Suppose one believed that human sacrifices were a necessary part of religious worship, would it be seriously contended that the civil government under which he lived could not interfere to prevent a sacrifice? Or if a wife religiously believed it was her duty to burn herself upon the funeral pile of her dead husband, would it be beyond the power of the civil government to prevent her carrying her belief into practice?

So here, as a law of the organization of society under the exclusive dominion of the United States, it is provided that plural marriages shall not be allowed. Can a man excuse his practices to the contrary because of his religious belief? To permit this would be to make the professed doctrines of religious belief superior to the law of the land, and in effect to permit every citizen to become a law unto himself. Government could exist only in name under such circumstances. . . .