The DOMA argument followed Tuesday's case over California's ban on same-sex marriage, a case in which the justices indicated they might avoid a major national ruling on whether America's gays and lesbians have a right to marry. Even without a significant ruling, the court appeared headed for a resolution that would mean the resumption of gay and lesbian weddings in California.
Marital status is relevant in more than 1,100 federal laws that include estate taxes, Social Security survivor benefits and health benefits for federal employees. Lawsuits around the country have led four federal district courts and two appeals courts to strike down the law's Section 3, which defines marriage. In 2011, the Obama administration abandoned its defense of the law but continues to enforce it.
Same-sex marriage is legal in the District of Columbia and in Connecticut, Iowa, Maine, Maryland, Massachusetts, New Hampshire, New York, Vermont and Washington state. It was legal in California for less than five months in 2008.
The justices chose for their review the case of Edith Windsor, 83, of New York, who sued to challenge a $363,000 federal estate tax bill after her partner of 44 years died in 2009.
Windsor, who goes by Edie, married Thea Spyer in 2007 in Canada after doctors told them that Spyer would not live much longer. She suffered from multiple sclerosis for many years. Spyer left everything she had to Windsor.
There is no dispute that if Windsor had been married to a man, her estate tax bill would have been zero.
The U.S. 2nd Circuit Court of Appeals in New York agreed with a district judge that the provision of DOMA deprived Windsor of the constitutional guarantee of equal protection of the law.
Like the Proposition 8 case from California, Windsor's lawsuit could falter on a legal technicality without a definitive ruling from the high court.
The House Republicans, the Obama administration and a lawyer appointed by the court especially to argue the issue spent the first 50 minutes Wednesday discussing whether the House Republican leadership can defend the law in court because the administration decided not to, and whether the administration forfeited its right to participate in the case because it changed its position and now argues that the provision is unconstitutional.
If the Supreme Court finds that it does not have the authority to hear the case, Windsor probably would still get her refund because she won in the lower courts. But there would be no definitive decision about the law from the nation's highest court, and it would remain on the books.
Roberts and Scalia seemed most interested in this sort of outcome.
On Tuesday, the justices weighed a fundamental issue: Does the Constitution require that people be allowed to marry whom they choose, regardless of either partner's gender? The fact that the question was in front of the Supreme Court at all was startling, given that no state recognized same-sex unions before 2003 and 40 states still don't allow them.
But it was clear from the start of that argument in a packed courtroom that the justices, including some liberals who seemed open to gay marriage, had doubts about whether they should even be hearing the challenge to California's Proposition 8, the state's voter-approved gay marriage ban.
Kennedy suggested the justices could dismiss the case with no ruling at all.
Such an outcome would almost certainly allow gay marriages to resume in California but would have no impact elsewhere.
There was no majority apparent for any particular outcome, and many doubts were expressed by justices about the arguments advanced by lawyers for the opponents of gay marriage in California, by the supporters and by the Obama administration, which is in favor of same-sex marriage rights. The administration's entry into the case followed President Barack Obama's declaration of support for gay marriage.
Reflecting the high interest in the cases, the court released an audio recording of Wednesday's argument, just as it did Tuesday.
A somewhat smaller crowd gathered outside the court Wednesday, mainly gay marriage supporters who held American and rainbow flags. "Two, four,six, eight, we do not discriminate," a group chanted at one point."If this isn't the time, when is the time? When does equality come into play?" asked Laura Scott, 43, of Columbia, Md.