Polygamy is the state of being married to more than one person at the same time. It is illegal in many countries. The following is a list of polygamy court cases:
Montcho case (July 11, 1980, n°16596) — Allowed family reunification for polygamous households.[3][4][5]
Philippines
Malaki and Salanatin-Malaki v. Philippines (2021) G.R. No. 221075 — established that the "a party to a civil marriage who converts to Islam and contracts another marriage, despite the first marriage’s subsistence, is guilty of bigamy"[6]
United Kingdom
Hyde v. Hyde (1866) {L.R.} 1 P. & D. 130 — established the modern understanding and legal definition of marriage
Bethell v. Hillyard (1885) 38 Ch.D. 220. [1885 B. 2119.] — a potentially polygamous marriage is void
R v Smith 1994 15 Cr App R (S) 407 — used divorce papers to marry again[7]
R v Cairns [1997] 1 Cr App R (S) — used polygamy to circumvent immigration controls[7]
Miles v. United States, 103U.S.304 (1880) — established that the second wife may testify as to her husband's bigamy, because their marriage is not de jure
Clawson v. United States, 114U.S.477 (1885) established that when the juror list is exhausted due to challenges of jurors for being supportive of polygamy, an open venire may be used, in which the U.S. Marshal summons jurors from the body of the judicial district
In re Snow, 120U.S.274 (1887) — multiple convictions overturned, as cohabiting was a continuous offense, and cannot be charged separately for individual years of offence
Davis v. Beason, 133U.S.333 (1890) — upheld ban on voting and holding political office in the Idaho Territory for all members of organizations that teach or advocate polygamy
In re Black, 3 Utah 2d 315 (1955) [283 P.2d 887][8] — raising children in a polygamist household is evidence of child neglect; the state can remove and retain custody of children while their parents unlawful cohabitation continues
Potter v. Murray City, 760 F.2d 1065 (10th Cir. 1985)[9] — "the State is justified, by a compelling interest, in upholding and enforcing its ban on plural marriage"
Barlow v. Blackburn, 165 Ariz. 351, 356, 798 P.2d 1360, 1365 (App.1990)[10] — "Barlow's practice of polygamy justif[ies] revoking or suspending his peace officer certification" as "Arizona's constitutional prohibition against polygamy is valid" and "Arizona's compelling state interest [...] justifies an infringement upon Barlow's religiously-motivated conduct"
Barlow v. Evans, 993 F.Supp. 1390 (D.Utah 1997)[12] — Fair Housing Act prohibition of religious discrimination does not provide protection for polygamists
Brown v. Buhman, 11-cv-0652-CW (2013)[14] — the portions of Utah's anti-polygamy laws which prohibit multiple cohabitation ruled unconstitutional, but Utah allowed to maintain its ban on multiple marriage licenses.[15][16][17][18]
Carrick v. Snyder, 5:2015cv10108, case before Michigan's Eastern District Federal brought by the Rev. Neil Patrick Carrick holding that it is a violation of the Free Exercise Clause of the First Amendment to prohibit clergy from performing same sex or polygamous wedding ceremonies.[19][20]
Collier et al v. Fox et al, 1:15-cv-00083, case brought by Nathan Collier et al in Montana District Court, seeking a marriage license for Nathan Collier and Christine Collier. Nathan Collier had a legal marriage with Victoria Collier. The case was denied as moot.[21]
Mayle v. Orr et al, 17-cv-00449,[22] brought by Kenneth Mayle in U.S. District 7 (Northern Illinois) seeking to strike Illinois laws on Bigamy,[23]Adultery,[24][25][26] and Fornication[27] based on religious beliefs, practice, and philosophies of Satanism and Thelema including Enochian Sex Magick. The complaint claims these laws violate the 1st and 14th amendment of the U.S. Constitution. The case was dismissed on 4/10/2017. An attempt at an appeal was denied on 11/3/2017 based on a procedural error.