It's a very complicated questions, since each of these nations interacts with a lot of other players besides the U.S.

Iran, as just one example, also has Israel to deal with, which is obvious. Less obvious is that other Arab nations don't want to see Iran make a big hairy thing of itself either. Remember who all fought on our side in the first Gulf war with Iraq, when Iraq was actively and obviously threatening its Arab neighbors. Of the thirty or so nations in the Coalition against Iraq, about eight were Arabic.

I have grown more optimistic about these things over the years. Keep in mind that through much of my life, World War III with the Soviets was often treated as a "when" not an "if."