Correctly realizing the US can't protect them, they are either looking for a better patron or, failing that, to become convincingly neutral. The administration has no cards left to play other than massive escalation, which will not go well.

UPDATE: WSJ reports that Saudi and Co. are back with the program. Who knows if that will last, or what if any kind of deal falls out of this.

UPDATE 2: Saudi proposes a GCC wide non-aggression pact with Iran. I suppose the fence-sitting is over.