When the U.S. Supreme Court ruled last summer against a Texas law that forbade private homosexual activities, Justice Antonin Scalia ominously predicted the decision would spell the end to laws against a list of other taboos, including polygamy.

The ruling, Scalia said, "effectively decrees the end of all morals legislation" and would likely require laws against "fornication, bigamy, adultery, adult incest, bestiality and obscenity" to be subsequently declared unconstitutional.

Using that train of thought, a Utah civil rights attorney has now asked U.S. District Judge Ted Stewart to pick up where Scalia left off and strike down the state's century-old ban on polygamy.

"Utah's statutory prohibitions make criminal personal sexual relationships between consenting adults," attorney Brian Barnard writes in a new court filing. "This prohibition of polygamist relationships is as unconstitutional as Texas' prohibition against homosexual sodomy because it criminalizes a private sexual relationship between consenting adults."

The court's June 2003 holding in Lawrence v. Texas has been invoked in several lawsuits and sparked interesting legal debates across the country. The Massachusetts Supreme Judicial Court relied heavily on the ruling to reach its November decision rejecting a ban on same-sex marriages in that state.

In January, Barnard filed a federal lawsuit on behalf of three Utahns who wish to participate in plural marriage. The married couple, along with the man's would-be second wife, sued after they were denied a marriage license by the Salt Lake County Clerk's Office.

Barnard on Friday filed a motion for summary judgment in the case asking Stewart to rule that, as a matter of law, the polygamy ban violates the trio's First Amendment rights to practice their religion and their 14th Amendment rights to be free from unwarranted government intrusion.

According to the filing, "Deeply held religious beliefs mandate that plaintiffs now enter plural marriage. Belief in and practice of polygamous marriage is a requisite for plaintiffs' exaltation and eternal salvation."

The couple has not been identified, but Barnard has said the married couple is each in their 60s and the woman in her late 40s.

The Utah Attorney General's Office, which represents Salt Lake County Clerk Sherrie Swensen and two deputy clerks in the action, has not yet filed a response to the lawsuit. It will also have an opportunity to respond to Friday's motion prior to oral arguments in the case.