Washington, D.C.—The Supreme Court heard oral argument today on Section 3 of the 1996 Defense of Marriage Act, which forbids the federal government from recognizing state-level same-sex marriages. Judging by what I saw in the courtroom this morning, DOMA could be in serious trouble.

“The question is whether or not the Federal government, under our federalism scheme, has the authority to regulate marriage,” declared Justice Anthony Kennedy, who repeatedly suggested that he saw DOMA as an unconstitutional federal intrusion on “the essence of the State police power.”

Notably, at least one member of the Court’s liberal wing appeared to share Kennedy’s worries about DOMA and federalism. “What gives the federal government the right to be concerned at all at what the definition of marriage is?” asked Justice Sonia Sotomayor.

The remainder of the Court’s liberal bloc, meanwhile, expressed doubt as to whether Section 3 of DOMA could survive under the searching judicial scrutiny required by the Court’s equal protection jurisprudence. For Justice Ruth Bader Ginsburg, DOMA amounted to a clear example of unequal treatment by the government. It’s “two kinds of marriage,” she said. “The full marriage, and then this sort of skim milk marriage.”

Justice Elena Kagan expanded on that point, emphasizing what she saw as DOMA’s discriminatory intent. “When Congress targets a group that is not everybody’s favorite group in the world,” she told Paul Clement, the attorney and former solicitor general arguing in defense of DOMA, “we look at those cases...with some rigor” to see if “Congress’ judgment was infected by dislike, by fear, by animus.” The Defense of Marriage Act, she continued, “sends up a pretty good red flag.”

Chief Justice John Roberts, on the other hand, appeared unwilling to rule against DOMA on either federalism or equal protection grounds. “Just to be clear,” Roberts asked Solicitor General Donald Verrilli, “you don’t think there is a federalism problem with what Congress has done in DOMA?” No, “we don’t,” Verrilli conceded, an answer that the chief justice may later emphasize if he drafts his own opinion in favor of upholding the law.

In addition to these major constitutional questions, the Supreme Court also waded into the thorny jurisdictional problems created by the Obama administration’s decision last year to stop defending DOMA in court while still enforcing it. In practical terms, Obama’s approach meant that Edith Windsor, the woman who brought the case, had to pay nearly $400,000 in taxes after her spouse died, money she would not have had to pay absent DOMA. So while the Obama administration now agrees with Windsor that the law is unfair, that has not stopped the federal government from taking her money.

That approach did not appear to impress any of the justices today. Obama’s enforce-but-don’t-defend stance could give you “intellectual whiplash,” quipped Justice Kennedy, while Chief Justice Roberts wondered why the president “doesn’t have the courage of his convictions...rather than saying, oh, we’ll wait till the Supreme Court tells us we have no choice.”

Unlike Tuesday’s oral arguments over California’s Proposition 8, however, where similar jurisdictional concerns may prevent the Court from ruling on the constitutional merits, that result seemed to be less likely for DOMA.

In the end, the combination of Kennedy’s federalism stance and Kagan’s equal protection analysis could prove to be more than enough to attract the five votes necessary to send Section 3 of the Defense of Marriage Act to its grave.

Watch Damon Root and Katherine Mangu-Ward discuss today's oral arguments and what they mean for marriage equality and personal freedoms: