Bush started the process of tearing Iraq apart and handing the South to Shia Iran. Obama/Clinton went whole hog and nearly finished the job with their "Arab Spring." But Putin stepped in b****-slapped the whole plan. The deep state, CIA wanted Trump to continue the stupidity, but he rightly is against it.
ISIS is a Saudis strategic tool. They don't have a proper Army that can go abroad and they only have oil as a modern strategic tool. So what else do they have? Their position as center of orthodox, Wahabbist Islam. They create Jihad groups to do their international dirty-work. They helped birth ISIS to take out Assad and check Iran and Hezbollah's power. Their opinion is - wants the job is done, they (and the their blue-eyed mercenaries in the USA) can clean up ISIS
I’m not sold on the theory that Saudi Arabia was instrumental in the origin of ISIS. Perhaps elements within SA, but not official policy. ISIS was a real threat to the royal family. There’s more evidence to the Muslim Brotherhood being its true source - which explains why the Obama administration (including Hillary) only had a policy of containment towards “the caliphate.” The ivy league intellectual community that has trained most of our governmental elite believe the West’s injustice towards the Middle East is the ultimate source of terrorism. Hence the desire to undo that “wrong” by creating a unified Muslim state to replace the old Ottoman. Why else was Sec of State Clinton allowing the US to be involved in arms smuggling in Libya as well as regime change? Why support the toppling of every ME government that has Western origin?