Lyle Denniston from the SCOTUS Blog thinks so:

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.