SALT LAKE CITY (AP) – The debate over constitutional restrictions on same-sex marriage has taken a peculiar turn here, where voters in one of the country’s most conservative states are being asked to consider more than morality when defining matrimony.

Utah is one of at least nine states set to vote on such an amendment this election. Missouri voters passed that state’s ban earlier this month.

But here the issue is complicated by a second part of the amendment that critics fear could endanger the rights of even heterosexual couples. Some say the amendment’s language would invalidate health benefits, inheritance rights, hospital visitation, medical decisions and tax benefits for heterosexual couples who may live together but aren’t traditionally married.

In addition to defining marriage as a union between one man and one woman, the Utah amendment stipulates that no other union could be recognized as a marriage or given the same legal equivalent.

Like other states considering amendments, Utah already has a law on the books banning same-sex marriage. But lawmakers say it’s essential to put the limiting language into the constitution to ensure that same-sex marriage won’t ever be recognized in the state even if it’s valid in states like Massachusetts.

The bill’s legislative sponsors, Sen. Chris Buttars, R-West Jordan, and LaVar Christensen, R-Draper, argue that the second part is necessary to protect the first part against simple changes in nomenclature that would confer upon same-sex couples the same rights as marriage, such as “civil unions.”

“Part two defends the language in part one by saying you can’t create these names and use them as a battering ram to the back door to compromise marriage,” Buttars said.

“Are you telling me that the definition of good law is one that that’s never got an action against it?” Buttars said. “Especially when you deal with someone that is backed by the ACLU.”

Still, it has concerned even some conservatives who would typically support the amendment. The state’s attorney general, Mark Shurtleff, has signed onto a joint statement with two candidates vying for his job denouncing the measure.

Shurtleff is a Republican who opposes same-sex marriage and supports an amendment banning it. But he says this one is so poorly crafted that it could erode the rights of heterosexual couples in Utah.

Critics say the amendment might affect a healthcare policy implemented last year extending medical benefits to domestic partners of University of Utah employees. Salt Lake City’s study of its own domestic partner benefits policy could also be scrapped.

Republicans upbraided Shurtleff for publicly denouncing the amendment, saying he should’ve spoken up while the measure was before the Legislature earlier this year.

The amendment was passed by a two-thirds majority, mostly on party lines, in both the House and Senate, and finalized in March at almost the last possible hour. At the time, some lawmakers expressed concern that it was going forward too fast. The issue had been before the Senate for only 23 days before they gave the nod.

“There’s so many questions it raises,” said House Minority Leader Brent Goodfellow, D-West Valley. “This is not, in my opinion, the process we should go through to change the constitution. If we’re going to change it, it should be done over a period of time, and it should be studied.”

In the weeks before the Nov. 2 ballot, ad hoc advocacy groups have vowed to maintain a high public profile in an attempt to sway voters. Amendment sponsors Christensen and Buttars have started a group called The Constitutional Defense of Marriage Alliance, which joined a separate entity called Yes! For Marriage.

The Utah Don’t Amend Alliance has been active on the other side of the issue, latching onto Shurtleff’s arguments and circulating a petition urging voters to defeat the amendment.