In 2013, penalties were removed for married people who cohabit with other adults that are treated as spouses, effectively decriminalizing polygamy. The ruling was due to a lawsuit by a reality television star named Kody Brown, who works on a show about his life as a polygamist.
The decision to reinstate the ban on multi-spouse families was intended to assist in other cases related to polygamy, including child abuse. The state specifically pointed to the case of Warren Jeffs, a polygamous church leader who was convicted of sexually assaulting young girls.
State authorities have long maintained that they will not go after polygamists who otherwise do not break the law.
The Browns have announced that they will appeal the ruling, taking it all the way to the Supreme Court, if they can.
"The underlying rights of religious freedom and free speech are certainly too great to abandon," their lawyer, Jonathan Turley said in a statement.
A woman who was formerly in a polygamist marriage argued for the ban, saying that people who face abuse within a plural marriage often are pressured not to report the incidences. She believes that the ban could get authorities a “foot in the door.”
"We have all been told over and over again, 'We need to protect the principle of plural marriage at any cost,'" Kristyn Decker told AP.
Court documents estimate there are about 30,000 polygamists in Utah.