Sorry, I can't agree. While I can agree that the U.S. is an imperialist power, I think you're putting far, far too much on Syria. Of course, the issue is complicated given sunni-shia relations, and yes SA wants Assad gone, but the U.S. would never risk the mess in Iraq over something so small.

SA on the other hand, yes, yes they would. IS isn't really their problem, not in any major way. As for Israel, I doubt they're heavily involved. IS is only strengthening Iran's power in Iraq, and while Assad wasn't an ally of Israel, he's not all that much worse than anyone else around Israel.