In any real legal sense, the Saudis have a casus belli, not us, and they don't seem to want war over it. We aren't doing shit overtly unless the UN authorizes force, and though Obama may ask for it, after the overreaching Colonialist Cluster**** that Libya became, I don't see the UN General Assembly authorizing use of force with us involved in it for a long time, even assuming he somehow prevented the ChiComs and Russkiis from vetoing it in the Security Council.
So yeah, he'd probably love to do something to get a poll bounce, however he's kind of a prisoner of all his past commitment to the UN and Bush-blaming on previous foreign policy decisions, so I don't think it's gonna happen.
I also don't think anything short of glassing the place would actually accomplish a damned thing, in fact it would invalidate any internal opposition still limping along as 'Tools of the Crusaders.'