A federal lawsuit challenging Hawaii laws reserving marriage for heterosexual couples could provide the U.S. Supreme Court a chance to definitively rule on whether same-sex couples have a constitutional right to marriage.

Gay marriage advocates hailed the two Supreme Court decisions Wednesday as a significant step toward marriage equality, but the justices did not rule on the fundamental issue of whether gay and lesbian couples can marry.

Lawyers representing the plaintiffs in the Hawaii case say some of the language in one of the rulings bolsters their chances of persuading federal appeals judges to overturn the state’s ban on same-sex marriages.

The federal lawsuit maintains that Hawaii marriage laws violate gay couples’ rights under the U.S. Constitution.

The lawsuit was thrown out by Senior U.S. District Judge Alan Kay last year, but the Hawaii case and a similar Nevada lawsuit are pending before the 9th U.S. Circuit Court of Appeals. They will be heard at the same time, but were suspended pending the high court rulings, according to John D’Amato, lawyer for the three plaintiffs in the Hawaii lawsuit: Natasha Jackson, Janin Kleid and Gary Bradley.

Opening briefs are due later this year and an appeals court ruling isn’t expected until next year at the earliest.

The losing side is expected to ask the Supreme Court to review the appeals court decision, which might place the constitutional issue of same-sex marriages directly before the justices.

Legalization of same-sex marriages here would end the Hawaii court case, rendering it moot.

But the Hawaii and Nevada challenges have progressed the farthest in the federal court system and would be on track to be the first to present the issue to the Supreme Court, D’Amato said.

The Hawaii case features the unusual dual positions of Gov. Neil Abercrombie, who favors the right to same-sex marriages, and Health Director Loretta Fuddy, who defends the state’s marriage laws.

In a statement, Abercrombie said he is "encouraged" that the language in one of Wednesday’s rulings supports his position that the "U.S. Constitution’s Equal Protection Clause requires same-sex marriage in all states, including Hawaii."

Fuddy said in a statement she respects the high court’s rulings and is reviewing them to determine "what impact, if any," the decisions will have on the Hawaii case.

"We will continue to defend and uphold the Constitution and the laws of the state of Hawaii," she said.

Abercrombie and Fuddy are represented by two separate team of deputies from the Attorney General’s Office.

One of the two landmark Supreme Court rulings struck down the Defense of Marriage Act’s provision that denies federal tax, pension and other benefits to legally married gay couples in about a dozen states that recognize such marriages.

The other ruling left intact a federal judge’s decision declaring California’s Proposition 8 to be unconstitutional, clearing the way for the resumption of same-sex marriages in that state.

James Hochberg, lawyer for Hawaii Family Forum, which was allowed to intervene in the Hawaii case to defend the state marriage laws, said he was still reviewing the ruling to determine how it might affect the case. But he said it was a "good thing" that the high court ruled "very narrowly."

"I think the court held back from the disastrous stuff," he said.

D’Amato and Deputy Attorney General Girard Lau said they will cite the high court’s Defense of Marriage Act ruling in their briefs to the appeals court.

"We think there’s very compelling language that provides strong support for the governor’s position," Lau said.

Justice Anthony Ken­nedy’s majority opinion said the Defense of Marriage Act places same-sex couples in a "second-tier marriage" and "humiliates tens of thousands of children now being raised by same-sex couples."

The U.S. Constitution, the opinion said, does not give the government the "power to degrade or demean in the way (DOMA) does."

Although the opinion deals with DOMA, the rationale might apply to whether same-sex couples have the constitutional right to marry, D’Amato said.

"It gives me hope that we can get a sympathetic hearing of our appeal at the 9th Circuit," D’Amato said.

Former Associate Justice Steven Levinson, who wrote the landmark 1993 ruling supporting gay marriage, which led Congress to pass DOMA in reaction, said he’s "ecstatic."

Levinson’s opinion paved the way for Hawaii to be the first state to legalize same-sex marriage until a 1998 constitutional amendment negated the ruling.

Levinson, who left the court in late 2008 and has been active in retirement supporting same-sex marriages, said he didn’t think the rulings would have much impact legally on the Hawaii case.

He said the high court’s majority made clear they weren’t addressing whether same-sex couples have a constitutional right to marriage. But he said the high court’s rulings provides momentum for Hawaii lawmakers to legalize gay marriages.

Hawaii recognizes civil unions that provide gays and lesbian couples with the same state benefits and rights as married couples.

With the court’s DOMA ruling, those couples could receive federal marriage benefits if lawmakers allow them to get married here, he said.

"I’m hoping it will provide a huge, tremendous incentive to the Legislature to take a simple step to achieve fairness," Levinson said.