In the case of Cleveland v. United States (1946), the U.S. Supreme Court upheld a federal law that criminalized polygamy, rejecting arguments by members of a religious sect who claimed their First Amendment rights were violated. The defendants, leaders in the Fundamentalist Church of Jesus Christ Latter-Day Saints, had been convicted under the Mann Act for transporting women across state lines for "immoral purposes," namely plural marriage ceremonies. They argued that because they sincerely believed polygamy was a religious duty, it should be protected as free exercise of religion under the First Amendment. The court disagreed and held that while laws cannot interfere with religious beliefs and opinions, they may regulate actions even if those actions are rooted in religious belief. It affirmed that Congress has broad power to maintain standards among states regarding what constitutes moral behavior and can enforce these standards through legislation like the Mann Act.

In the dissenting opinion for Cleveland v. United States, Justice Wiley Rutledge argued that the majority's interpretation of the Mann Act was too broad and could potentially criminalize innocent actions. He contended that Congress intended to target commercialized vice, not punish individuals for private moral transgressions or religious practices such as polygamy. Rutledge believed that applying a broader interpretation would lead to an invasion of personal liberties by allowing federal regulation over private morality issues traditionally left to state law enforcement. Furthermore, he expressed concern about potential misuse of this expanded power in future cases beyond those involving polygamy or other unconventional marital arrangements.