Most observers expect the court to strike down DOMA as a violation of the right of states to regulate marriage and dismiss the Prop 8 appeal on a technicality, leaving same-sex marriage legal in California.
Either way, the bottom line seems to be that the impact on Utah is likely to be nil.
"We think it is more likely to be a narrow construction," Utah Attorney General John Swallow said Monday. "States like Utah that have not yet allowed same-sex marriage to be recognized legally [would] continue to define marriage as between one man and one woman, as Utah has."
In the DOMA case, an appeals court ruled it was unconstitutional to deny federal benefits to gay and lesbian couples in states that recognize same-sex marriage as valid.
In the Prop 8 matter, an appeals court upheld a trial judge's ruling that a 2008 voter-approved, LDS Church-backed ban on same-sex marriage in California was unconstitutional.
"The DOMA ruling is not going to affect the law in Utah at all," said Cliff Rosky, a professor at the University of Utah's law school and board member of Equality Utah. "DOMA is a federal law that determines if same-sex couples married in other states [with gay marriage] will get federal benefits."
Those benefits, he said, include filing of joint tax returns, access to federal insurance, Social Security survivors' benefits and being able to apply for immigration status for their same-sex partners.
If the court derails DOMA as many predict how far it goes in grounding its decision will be key. If the decision is narrowly tailored, it may result in a patchwork of decisions by federal agencies and programs about how to apply the ruling particularly in states such as Utah that don't allow or recognize same-sex marriage.
"There would be no general law for this," Rosky said, "and it would ultimately be up to Congress and each federal agency to decide."
At present, 12 states, along with Washington, D.C., have legalized same-sex marriage.
Some federal agencies allow state law to lead policy decisions. One example: The Social Security Administration has used state inheritance laws to determine whether children conceived by in-vitro fertilization after a parent's death qualify for Social Security benefits in that parent's name. In Utah, the answer is no, though probate law in some other states do allow such claims.
If DOMA is rejected, Rosky said, "It doesn't mean you get all the federal benefits in Utah."
But Rosky said that if the court were to rule on a broad basis that DOMA or Prop 8, for that matter violated the equal-protection clause of the U.S. Constitution, its decision could be used as the basis to challenge Utah's Amendment 3 ban on same-sex marriage.
But "very few expect that," Rosky said.
Lynn Wardle, a law professor at LDS Church-owned Brigham Young University, agrees.
"I would be very surprised if they [ruled on] the merits and said Proposition 8 is unconstitutional and voters can't define marriage," said Wardle, who helped "a little bit" with Utah's Amendment 3, consulted on DOMA and filed an amicus brief in the high court cases on behalf of a group of lawyers. "If it's on obscure procedures or principles such as standing, it probably won't have a great impact on the same-sex marriage debate pro or con. ... True believers on both sides are going to try to distill something from it to try to reinforce their views, but I doubt it will have much substantive decision-making."
As for DOMA, Wardle said, it is clear that constitutionally the regulation of family law is a state right, but the federal government does have the power to define the terms used in marriage law.
"On the merits, to say Congress doesn't have that power is really unprecedented, really dramatic," he said. "On the merits, it's a slam-dunk yes. On the politics, it's a whole lot more complicated."
But, Wardle added, it is hard to imagine how tossing out DOMA would have an impact on Utah law since the decision would, in essence, say the federal government doesn't have the authority to regulate marriage and has to respect and incorporate state law.
"I don't think it will affect any of Utah's constitutional amendments or statutes," he said.
Karen McCreary, executive director of the American Civil Liberties Union of Utah, said that although the court may not issue rulings that provide broad, general protections, other strategies are in place to work toward equality for same-sex couples in states such as Utah.
"We are definitely hopeful that there will be some good, affirming progress made [in the rulings]," she said, while in Utah "We will continue to work to educate and get support for understanding and nondiscrimination. ... Those are areas we can work on here. It's maybe not quite the marriage arena, but there is other work to do here."
That includes working to end discrimination in housing and employment, Rosky said, which 90 percent of the public already believes is illegal.
"It's not," Rosky said. "It's still legal in the state of Utah to evict or fire someone because of their sexual orientation."
Salt Lake City, with the blessing of the LDS Church, Salt Lake County and a number of other local Utah governments have approved laws banning housing and job discrimination against gays and transgender residents.
Rosky said the grass-roots movement in favor of marriage and other rights for same-sex couples is being won at the ballot box, bypassing the nation's highest court.
"There is already a clear shift in favor of allowing same-sex couples to marry," Rosky said. "We've seen it in one state after another. With or without the justices of the Supreme Court, that is the way it is going. ... And that is a huge development more significant than any Supreme Court decision."
Utah case still pending
Among those eagerly awaiting the decisions from the U.S. Supreme Court are three couples in Utah who filed a federal lawsuit in March challenging the state's ban on same-sex marriage, which they say denies them basic rights.
They want a federal judge to declare unconstitutional any state law barring same-sex marriage.
In 2004, Utah voters approved an amendment to the state's constitution prohibiting same-sex marriage.
The plaintiffs in the Utah case are Karen Archer and Kate Call, who were legally married in Iowa; Derek L. Kitchen and Moudi D. Sbeity; and Laurie Wood and Kody Partridge. The latter two couples are both in long-term, committed relationships. They argue the amendment violates the 14th Amendment to the U.S. Constitution.
In addition to depriving residents of access to state-sanctioned marriages, the Utah law violates the rights of same-sex couples who were legally married in other states, the complaint says.
The plaintiffs in the case have given the state 45 days after the U.S. Supreme Court rulings to respond to the lawsuit, according to Utah Attorney General John Swallow.
"Once that ruling comes down," Swallow said, "we will analyze it very carefully and decide how we are going to approach the defense of Amendment 3."