Edmunds Act

The Edmunds Act, also known as the Edmunds Anti-Polygamy Act of 1882, is a United States federal statute, signed into law on March 23, 1882 by president Chester A. Arthur, declaring polygamy a felony. The act is named for U.S. Senator George F. Edmunds of Vermont. The Edmunds Act also prohibited "bigamous" or "unlawful cohabitation" (a misdemeanor), thus removing the need to prove that actual marriages had occurred. It was passed in a wave of Victorian-era reaction to the perceived immorality of polygamy, or at least polygyny, which was often compared to slavery.

The act not only reinforced the 1862 Morrill Anti-Bigamy Act but also revoked polygamists' right to vote, made them ineligible for jury service, and prohibited them from holding political office.

A claim was made that the law violated the constitutional prohibition on ex post facto laws; that is, polygamists were charged for polygamist marriages solemnized before passage of the statute. A challenge to the statute was framed on these and other grounds. The Supreme Court ruled, in Murphy v. Ramsey, 114 U.S. 15 (1885), that the statute was not ex post facto because convicts were charged for their continued cohabitation, not for the prior illegal marriage. Some modern scholars suggest the law may be unconstitutional for being in violation of the Free Exercise Clause.