The new case was brought on behalf of Edith Windsor of New York City, who married her longtime partner, Thea Clara Spyer, in 2007 in Canada. When Ms. Spyer died in 2009, Ms. Windsor inherited her property. Because the Internal Revenue Service was not allowed, under the Defense of Marriage Act, to consider her a surviving spouse, she faced a tax bill of $363,053 that she would not have had to pay if the marriage had been recognized.

Because the Supreme Court now has disagreement among circuits on a major issue of law involving the Defense of Marriage act, “this makes it more likely” that the Supreme Court will take up the cases, said Douglas NeJaime, an associate professor of law at Loyola Law School in Los Angeles. He said the most important justice in consideration of marriage cases was likely to be Justice Anthony Kennedy, who has sided with the liberal majority on such cases as Lawrence v. Texas, in which he wrote the opinion that struck down state sodomy laws.

As Justice Kennedy has proved mindful of federalism issues, Professor NeJaime said, he might be reluctant to take a case in which federal courts have struck down a state law like Proposition 8, in California. The Defense of Marriage Act cases, by contrast, struck down a federal law, and any decision by the Supreme Court would have an effect only in states that allow same-sex marriage. “This is the kind of case that would appeal to Justice Kennedy for the court’s first intervention on same-sex marriage,” he predicted.

It could also be a likelier case for the court to take instead of the First Circuit case because it could be heard by the full court, Professor NeJaime said. Justice Elena Kagan might recuse herself from hearing the First Circuit case because of her former role as solicitor general, leaving the possibility that the other justices could find themselves in a 4-4 tie.

Congress passed the Defense of Marriage Act in 1996, and in 2010 a federal judge in Massachusetts struck down the law as unconstitutional, declaring that restrictions on same-sex marriage had no rational basis and failed even the most lenient test for constitutional scrutiny. That decision was upheld in May 2012 by the Court of Appeals for the First Circuit, which also declared the act unconstitutional.