When the U.S. Supreme Court struck down Texas' law against sodomy last year, at least one justice foresaw the likes of Brian Barnard.

Justice Antonin Scalia warned that the ruling would unleash a wave of challenges to state laws against "bigamy, same-sex marriage, adult incest, prostitution, masturbation, adultery, fornication, bestiality, and obscenity."

Sure enough, Barnard, a civil rights attorney, has brought a lawsuit challenging Utah's ban on polygamy (search). And some legal experts say thter into a plural marriage but were denied a marriage license by Salt Lake County clerks.

Citing the high court's decision last June in Lawrence v. Texas (search), the lawsuit claims the county violated the plaintiffs' right to privacy with regard to intimate matters and trampled on their First Amendment right to religious freedom.

Barnard has not disclosed his clients' faith except to say that polygamy is a "sincere and deeply held religious major tenet." Utah's constitution bans polygamy, and a 113-year-old Supreme Court ruling holds that the First Amendment does not protect the practice.

Polygamy was part of the early beliefs of Mormon Church (search) but was abandoned in 1890 as the Utah territory sought statehood. The church now excommunicates members who practice it and has worked feverishly to distance itself from the estimated 30,000 polygamists across the West who say they are following fundamental Mormon doctrine.

Utah Attorney General Mark Shurtleff filed a friend-of-the-court brief in the Lawrence case, arguing that overturning the Texas law would open the door to challenges of Utah's polygamy ban.

Shurtleff said he believes Barnard's case is headed for the Supreme Court, and predicted the justices would uphold the polygamy ban.

"We have a long line of cases saying that the institute of marriage is the bedrock of society. Therefore, states have a compelling interest in regulating and controlling marriage," he said.

But at least one legal expert said Lawrence's logic leads to the legalization of polygamy, since the high court held that morality is not a strong enough justification for the state to ban a practice deemed unpopular or immoral by the majority.

"It's not a case people can sniff at," said Richard G. Wilkins, a law professor at Brigham Young University. "If you can't require monogamy, how in the world can you deny the claims of the polygamists, particularly when it's buttressed by the claim of religion?"

Others say Barnard will have a hard time taking the court's reasoning from the bedroom and applying it to marriage. The Lawrence case involved private behavior: Two gay men were arrested after police entered their apartment and found them having sex.

"It's possible to take the concept of private and intimate relationships and extend it to marriages, but we're not there yet," said Wayne McCormack, a law professor at the University of Utah.

The state could try to justify the ban on polygamy by citing the messiness of configuring property rights and benefits between multiple spouses, McCormack said.

In one of the most sensational polygamy cases in Utah in recent years, Tom Green, who had five wives, went to prison for bigamy, child rape and failure to pay child support for 28 of his children.

But Barnard has some advantages, too: While polygamy cases in Utah have sometimes been fraught with claims of rape, unlawful sex with a minor or welfare fraud, Barnard's lawsuit involves consenting adults and no such allegations.

Dani Eyer, executive director of the ACLU of Utah, which is not a party to the case, said the state will "have to step up to prove that a polygamous relationship is detrimental to society."

"There's no denying that thousands and thousands are doing that here and will maintain that it's healthy," she said. "The model of the nuclear family as we know it in the immediate past is unique, and may not be necessarily be the best model. Maybe it's time to have this discussion."