BOSTON >> Fresh from a favorable ruling by a federal appeals court, Dorene Bowe-Shulman can’t wait for the U.S. Supreme Court to weigh in on whether same-sex married couples should get the same federal benefits as heterosexual couples.

“I really look forward to the next step,” said Bowe-Shulman, one of 17 people from Massachusetts who sued to challenge the constitutionality of the federal Defense of Marriage Act.

On Thursday, the 1st U.S. Circuit Court of Appeals found that the law’s denial of an array of federal benefits to same-sex couples is unconstitutional, affirming a ruling by a federal judge in 2010. Opponents and supporters of gay marriage said the case is now almost certainly headed to the Supreme Court.

Bowe-Shulman, 46, said she wants the case to go before the Supreme Court because it will put a national spotlight on the law and “expose the injustice of DOMA to more people.”

Bowe-Shulman said she and her wife pay about $100 more in taxes each month because she is taxed as part of her wife’s health insurance.

“The harm that DOMA has done hasn’t been so apparent to the general public,” she said.

In a unanimous ruling, a three-judge panel of the 1st Circuit found that the 1996 law deprives gay couples of the rights and privileges granted to heterosexual couples.

The court did not rule on another provision of the law that says states without same-sex marriage cannot be forced to recognize gay unions performed in states where it is legal. The court also was not asked to address whether gay couples have a constitutional right to marry.

The law was passed a time when it appeared Hawaii would legalize gay marriage. Since then, many states have instituted their own bans on gay marriage, while eight states have approved it, led by Massachusetts in 2004 and continuing with Connecticut, New York, Iowa, New Hampshire, Vermont, Maryland, Washington state and the District of Columbia. Maryland and Washington’s laws are not yet in effect and may be subject to referendums.

The 1st Circuit agreed with U.S. District Judge Joseph Tauro, who concluded that the law interferes with the right of a state to define marriage and unconstitutionally denies gay couples federal benefits given to heterosexual couples, including the ability to file joint tax returns.

The ruling came in two lawsuits, one filed by the Boston-based legal group Gay & Lesbian Advocates & defenders and the other by state Attorney General Martha Coakley.

“For me, it’s more just about having equality and not having a system of first- and second-class marriages,” said plaintiff Jonathan Knight, a financial associate at Harvard Medical School who married Marlin Nabors in 2006.

“We can do better, as a country, than that,” said Knight, who estimates that the law costs the couple an extra $1,000 a year.

Opponents of gay marriage criticized the decision.

“This ruling that a state can mandate to the federal government the definition of marriage for the sake of receiving federal benefits, we find really bizarre, rather arrogant, if I may say so,” said Kris Mineau, president of the Massachusetts Family Institute.

Last year, President Barack Obama announced that the Department of Justice would no longer defend the constitutionality of the law. After that, House Speaker John Boehner convened the Bipartisan Legal Advisory Group to defend it. The legal group argued the case before the appeals court.

White House spokesman Jay Carney said the appeals court ruling is “in concert with the president’s views.” Obama, who once opposed gay marriage, declared his unequivocal personal support in recent weeks. Carney wouldn’t say whether the government would actively seek to have the law overturned if the case goes before the Supreme Court. 

“I can’t predict what the next steps will be in handling cases of this nature,” Carney said. 

The 1st Circuit said its ruling would not be enforced until the Supreme Court decides the case, meaning that same-sex married couples will not be eligible to receive the economic benefits denied by the law until the high court rules. Only the Supreme Court has the final say in deciding whether a law passed by Congress is unconstitutional. 

Until Congress passed the law, “the power to define marriage had always been left to individual states,” the appeals court said in its ruling. 

“One virtue of federalism is that it permits this diversity of governance based on local choice, but this applies as well to the states that have chosen to legalize same-sex marriage,” Judge Michael Boudin wrote for the court. “Under current Supreme Court authority, Congress’ denial of federal benefits to same-sex couples lawfully married in Massachusetts has not been adequately supported by any permissible federal interest.” 

Several times in its ruling, the appeals court noted that the case will probably end up before the high court, at one point saying, “only the Supreme Court can finally decide this unique case.” 

Paul Clement, a Washington, D.C., attorney who defended the law on behalf of the Bipartisan Legal Advisory Group, argued that Congress had a rational basis for passing the Defense of Marriage Act in 1996, when opponents worried that states would be forced to recognize gay marriages performed elsewhere. 

The group said Congress wanted to preserve a traditional and uniform definition of marriage and has the power to define terms used to federal statutes to distribute federal benefits. 

“But we have always been clear we expect this matter ultimately to be decided by the Supreme Court, and that has not changed,” he said in a statement. 

Two of the three judges who decided the case Thursday were Republican appointees, while the other was a Democratic appointee. 

In California, two federal judges have found this year that the law violates the due-process rights of legally married same-sex couples. 

In the most recent case, a judge found the law unconstitutional because it denies long-term health insurance benefits to legal spouses of state employees and retirees. The judge also said a section of the federal tax code that makes the domestic partners of state workers ineligible for long-term care insurance violates the civil rights of people in gay and lesbian relationships. 

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Associated Press writers Jay Lindsay and Shannon Young contributed to this report.