English common law courts in 1964 made bigamy, or marrying while an undivorced spouse is still living, a felony, states Brigham Young University. When the United States gained independence, the states adopted laws against bigamy. The Morrill Act of 1862 made bigamy punishable by fine and prison time.
The Morrill Act was challenged but upheld in 1879, during Reynolds v. United States, despite the defendant's argument that the law violated the free exercise of religion for Mormons who supported plural marriage, claims BYU. The Edmunds Act of 1882 made bigamous cohabitation a misdemeanor and resulted in 1,300 Latter-day Saints jailed in the 1880s.