But it appeared that at least five justices — Justice Kennedy and the court’s four more liberal members — had great difficulty accepting Mr. Clement’s line of reasoning, even as nine states and the District of Columbia have now legalized same-sex marriage.
“What gives the federal government the right to be concerned at all with what the definition of marriage is?” asked Justice Sonia Sotomayor.
Another issue explored by justices was the “sea change” in the popular attitudes about gay marriage since 1996, and whether that was the result of the “political effectiveness” of gay-rights advocates.
Attorney Roberta Kaplan, representing Ms. Windsor, downplayed the influence of advocates. The nation’s sea change on gay marriage is due to a “societal understanding” that came from places beyond political power of gay people, she said.
Chief Justice John G. Roberts Jr. was skeptical: “As far as I can tell, political figures are falling over themselves to endorse your side of the case.”
The political-power question is important because one of the tests to give sexual orientation a heightened level of scrutiny is that the group is politically powerless.
The impetus for DOMA — especially the extent of “moral disapproval” noted in a 1996 House report accompanying its debate on the measure — was also examined.
“Is that what happened in 1996?” Justice Elena Kagan pointedly asked Mr. Clement.
Such language appears in the House report, he replied, “and if that’s enough to invalidate the statute, then you should invalidate the statute. But that has never been your approach.”
Ms. Kaplan agreed that “moral disapproval” was a factor in the 1996 vote — DOMA “was enacted to defend against the marriages of gay people,” she said. But when asked by Chief Justice Roberts if she believed that 84 senators who voted for DOMA based their vote on moral disapproval of gay people, she softened her response. “I’m not saying it was animus or bigotry; I think it was based on a misunderstanding of gay people.”
Earlier in the session, the court queried Mr. Clement and two other attorneys on whether the Windsor case was properly before them, and whether the House of Representatives had legal “standing” to defend DOMA in light of the Obama administration’s refusal to do so.
Mr. Clement argued that the House has historically had the ability to defend its laws, especially when the executive branch declines to do so.
But court-invited amicus Harvard Law School professor Vicki C. Jackson said the House of Representatives had no “injury,” and the Obama administration wasn’t asking the court to redress any injuries either. “There is no justiciable case before this court,” said Ms. Jackson, adding that it should “await another case, another day to decide this question.”
Deputy Solicitor General Sri Srinivasan, arguing for the administration, said the high court should issue a ruling on DOMA, and that there is precedent for the executive branch to not defend a law even while it was enforcing it. But Chief Justice Roberts challenged that line of argument, saying the high court was being asked to do something “totally unprecedented.”