SALT LAKE CITY >> Utah prosecutors are invoking jailed polygamous leader Warren Jeffs as proof that plural marriage should be illegal in the state as they make arguments in a case brought by the stars of reality TV show “Sister Wives.”

The state argues in a filing Tuesday to a federal appeals court in Denver that Jeffs’ actions show what can happen when polygamy is allowed. Jeffs is serving a life sentence in a Texas prison for sexually assaulting underage girls he considered wives.

The state is challenging a 2013 ruling that struck down a key part of Utah’s law banning polygamy, bringing the state’s law in lines with other states.

About Jeffs, state attorneys wrote: “That is what the boots on the ground fact of bigamy and polygamy can look like.”

They added that the sect he still leads from prison on the Utah-Arizona border is “a community ravaged by untold fraud and other crimes associated with larger polygamous groups. The harms are real,” wrote Parker Douglas, the federal solicitor for the Utah Attorney General’s Office.

Kody Brown and his four wives, who brought the case, argue in court documents that their reality TV show “Sister Wives” shows polygamous marriages can be as healthy as monogamous ones.

The Browns have never been followers of Jeffs, who leads the Fundamentalist Church of Jesus Christ of Latter-Day Saints, of FLDS. The Browns belong to a different polygamous group, the Apostolic United Brethren, or AUB, that has a better reputation.

The state’s filing comes after Jonathan Turley, an attorney for the Browns, argued in a filing that the landmark U.S. Supreme Court ruling legalizing same-sex marriage shows that laws restricting consensual adult relationships are outdated, even if certain unions are unpopular.

It’s unclear when the appeals court will rule. No hearing has been set for the case.

Turley has said the family is prepared to take the legal fight to the U.S. Supreme Court if necessary.

Unlike same-sex marriage advocates, the Browns are not seeking full legal recognition of polygamous marriages.

The December 2013 ruling decriminalized polygamy, but bigamy — holding marriage licenses with multiple partners — remains illegal. In his decision, U.S. District Judge Clark Waddoups ruled that a portion of Utah’s bigamy law forbidding cohabitation with another person violated the First Amendment, which guarantees the freedom of religion.

If the ruling stands, Utah’s law would be identical to most other states that prohibit people from having multiple marriage licenses. In most polygamous families in Utah, the man is legally married to one woman but only “spiritually married” to the others.

Advocacy groups for polygamy and individual liberties called the ruling a significant decision that removed the threat of arrest for the state’s plural families.

Utah Attorney General Sean Reyes appealed, saying courts have long upheld laws banning polygamy because they prevent abuse of women and children.

The teaching that polygamy brings exaltation in heaven is a legacy of the early Mormon church, but the mainstream Salt Lake City-based Church of Jesus Christ of Latter-day Saints abandoned the practice in 1890 and strictly prohibits it today.

The state points to Utah’s prohibition on polygamy in the late 1800s, which allowed it to finally earn statehood, as another reason why the ruling should be overturned. Laws passed that prohibited plural marriages should make the court’s decision an easy one, the state contended.

“Utah has ever since lived with that condition and found that it curtails public harms that flow from polygamist and plural marriages,” the state filing says.