Audio is here, and the transcript is here (in pdf form).
From Lyle Denniston at SCOTUSblog:
If the Supreme Court can find its way through a dense procedural thicket, and confront the constitutionality of the federal law that defined marriage as limited to a man and a woman, that law may be gone, after a seventeen-year existence. That was the overriding impression after just under two hours of argument Wednesday on the fate of the Defense of Marriage Act.
That would happen, it appeared, primarily because Justice Anthony M. Kennedy seemed persuaded that the federal law intruded too deeply into the power of the states to regulate marriage, and that the federal definition cannot prevail. The only barrier to such a ruling, it appeared, was the chance – an outside one, though — that the Court majority might conclude that there is no live case before it at this point. […]
Justice Kennedy told Clement that there was “a real risk” that DOMA would interfere with the traditional authority of states to regulate marriage. Kennedy also seemed troubled about the sweeping breadth of DOMA’s Section 3, noting that its ban on benefits to already married same-sex couples under 1,100 laws and programs would mean that the federal government was “intertwined with citizens’ daily lives.” He questioned Congress’s very authority to pass such a broad law.[…]
Along with sharply negative comments about DOMA by the Court’s four more liberal members, Kennedy’s stance could put the law on the edge of constitutional extinction. But, if the Court were to do that based on states’ rights premises, the final ruling might not say much at all about whether same-sex couples were any closer to gaining an equal right to marry under the Constitution.[…]
The Justices seemed somewhat at odds over whether they do have the authority to go ahead with this case, so the possibility remained that the Court in the end could choose not to decide the merits of the law’s validity. That portion of the argument focused on just who in Congress, if anyone, could be in court to defend a federal law when the executive branch chose not to do so.
The Court’s decisions on both same-sex-marriage-related cases are expected to be announced in June. Although Court-watchers think they can see where things are going from the oral arguments, we really can’t know for sure until the decisions are made public.