Polygamy, the practice of having multiple spouses, is illegal in all 50 states in the United States. The Supreme Court ruled in 1878 that polygamy is not protected by the First Amendment's guarantee of religious freedom, and since then, polygamy has been universally outlawed in the U.S. Despite that, there are still some polygamist communities that exist, primarily in the Western states.

U.S. law currently handles polygamy by prosecuting it as a crime. Polygamists can face charges of bigamy, adultery, and child abuse, and they can be sentenced to prison or fines. However, because polygamy is often practiced within religious communities, there are some legal challenges to prosecuting it. For example, the First Amendment protects religious freedom, and some people argue that polygamy is a religious practice that should be protected.

In addition, some polygamists argue that their relationships are consensual and that they do not harm anyone. They say that they should be allowed to live their lives as they choose, without interference from the government.

The debate over polygamy is complex and there are many different perspectives on it. U.S. law has consistently taken the position that polygamy is illegal, but the issue remains a controversial one, and the question of how it should be addressed remains open.