Saudi Arabia sees ISIS as an existential threat. It has a reason to be scared, ISIS is a Wahabi jihad with updated technologies (social media) and techniques (open development). That means when push comes to shove, Saudi troops will either a) turn tail and run or b) join up in droves. To avoid this, the Saudis might attempt something radical:
- Build a completely useless multi-billion dollar wall around the country. Oh wait, they are already doing that.
- Ramp support for al Qaeda. Optimally, a big al Qaeda on a western target would force the US to fully engage ISIS, since ISIS is a physical target and al Qaeda isn't. Was al Qaeda's attack on Charlie Hebdo (and the Jewish deli) a Saudi funded endeavor to start the process?
- Hire western mercenaries to push ISIS around. Erik Prince has been trying to sell this option for years and is waiting in the wings to get it going. A few billion spent this way might be sufficient to turn the tide on ISIS.