From Glenn Greenwald at C & L: 

Ever since the Supreme Court in the Hamdan case ruled that the Bush administration’s Guantanamo Bay military commissions violate both federal law and the Geneva Conventions, the President has been paying lip service to his "willingness" to comply with that ruling.  But the Court’s ruling goes far beyond the limited question of whether military commissions are legal.  To arrive at its decision, the Court emphatically rejected the administration’s radical theories of executive power, and in doing so, rendered entirely discredited the administration’s only defenses for eavesdropping on Americans without the warrants required by law. 

Actual compliance with the Court’s ruling, then, compels the administration to immediately cease eavesdropping on Americans in violation of FISA.  If the administration continues these programs now, then they are openly defying the Court and the law with a brazeness and contempt for the rule of law that would be unprecedented even for them

Not sure if I agree with his whole premise from a legal perspective, but he raises a number of interesting points.  It’s a bit long, but well researched and I’d recommending reading the whole thing.