The basic deal between the US and SA is, in exchange for supplying the global oil market, the US will overlook SA's dictatorship, human rights abuses, and involvement in 9/11, and will supply them with weapons. If SA stops upholding its side of the deal, I would expect the Arab Spring would suddenly find its way to SA. Or, perhaps first, the US would support a coup against MBS to replace him with a more compliant member of the House of Said.