(CNN)A law effectively decriminalizing bigamy, when two people marry while at least one of them is already legally married, is now in effect in Utah.
For decades, bigamy was a third-degree felony, legally punishable by up to five years in prison and up to a $5,000 fine. The new law makes it an infraction, putting the offense on par with getting a traffic ticket.
The bill was signed into law by Gov. Gary Herbert in March and took effect on Tuesday.
Polygamy has been practiced in Utah by certain religious groups since before it became a state and continues to persist to this day.
Though the practice has long been illegal under state and federal law, the Utah attorney general's office has declined to prosecute the offense, except when it's committed along with other crimes.
The new law makes the attorney general's policy official. Supporters of the law say that reducing the penalty for bigamy removes barriers that previously prevented potential abuse victims from coming forward for fear of prosecution.
Bill's sponsor called previous law unenforceable
The bill passed the Legislature in February with overwhelming support, though it faced some opposition from advocacy groups who argued it normalized what they called an inherently oppressive practice and enabled the abuse of women and children.
Republican state Sen. Deidre Henderson, the bill's lead sponsor, called Utah's previous law unenforceable, saying that it didn't prevent people from engaging in polygamy, but instead isolated polygamous communities and prevented potential victims from reporting abuse.
"Vigorous enforcement of the law during the mid-twentieth century did not deter the practice of plural marriage," she wrote in an email to CNN in February.
"Instead, these government actions drove polygamous families underground into a shadow society where the vulnerable make easy prey. Branding all polygamists as felons has facilitated abuse, not eliminated polygamy."
Henderson wrote in an op-ed for The Salt Lake Tribune in February that some current and former polygamists had shared with her that they had been abused, but had faced pressure from their families to keep it a secret for fear of the potential consequences they could face in reporting to law enforcement.
"The history of raids and family separations, combined with the blanket ban on an entire lifestyle, leads to the fear that an investigation might break up an entire family, removing the children and incarcerating the parents," Henderson wrote. "That's a high hurdle, and so abuse is kept quiet."
Henderson added that she was not looking to legalize polygamy or the issuing of multiple marriage licenses, but was trying to "address the human rights crisis our law has created."
The new law codifies the Utah attorney general's policy of generally not prosecuting the crime of bigamy, except when committed along with other crimes, such as child abuse or sexual assault, or under false pretenses. It increases penalties in such cases.
"The intent of the bill is to eliminate the fear of arrest, imprisonment and having children removed into state custody in order to encourage more reporting, make investigating abuse easier, and lower the high barrier to community integration," Henderson told CNN in February.
Opponents say the bill normalizes polygamy
The Sound Choices Coalition, a nonprofit organization opposed to polygamy, condemned the decriminalization of bigamy when the bill was passed in February.
"This is abhorrent to us, many polygamist victims and other Utahn's who recognize that religious polygamy, as practiced in Utah and around the country, is responsible for many serious human rights violations," the organization said in a news release.
"Most who are living in these fundamentalist polygamous groups and families, are treated as property, forced to work without pay, traded as daughters, coerced into having unwanted sex, and into giving birth to numerous children they can not care for."
The organization called the bill a step toward legalizing the practice of polygamy and said it was concerned that the legislation would allow polygamy to grow.