The clerics are already basically in charge of Saudi Arabia. The Saudi Royals have to pay them tribute in exchange for the cleric's approval and support. Support of the mullahs is all that keeps the royals in power. They know full well that as soon as the money stops flowing, the clerics will declare the royals apostate, and the House of Saud will come crashing down.
Now, where does all of that money go once the royals have paid their tribute to the clerics? Into the pockets of ISIS, Al Qaeda, Boku Haram, and every other Wahhabi jihadist movement on the planet. It doesn't matter that the Saudi Royals "oppose" Al Quaeda or ISIS (and they don't oppose them nearly as much as they do any Shi'ite movement). It's Saudi money that made these organizations possible.
I believe it is U. S. money as well as arms. I’m not denying Saudi involvement from certain players, but I do think we made a huge mistake when we sent in arms and finances to the people fighting Assad.
ISIS seemed to literally explode on the scene directly after that. Obama and McCain, masters of the universe, screwed up again just like they did in Libya.