United States Supreme Court
1879

The Mormons argued that since polygamy was not only a belief but also a religious duty, it was protected by the First Amendment’s Free Exercise Clause. On January 6, 1879, the Court ruled, unanimously, against the Mormon Church. Reynolds v. United States upheld all of the anti-Mormon legislation. The opinion of Chief Justice Morrison Waite stated:

[…] 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. […]

Full text of Reynolds v. United States

Source(s):

Reynolds v. United States, 98 US 145 (1878).