Let the Shia and Sunni have at one another. Iran will enter the fight on the side of the Iraqi Shia, and the moderate Sunnis in Iran will soon enough turn on the radical SOB’s with whom they are now partnered. So, first it will be Shia vs Sunni and that will end in a stalemate; then crazy Sunnis will fight somewhat less crazy Sunnis. I don’t care who wins or how it turns out. Furthermore, it makes no difference. The Israelis are not going to let Iran develop a nuclear weapon; they will bomb Iran into the Stone Age. This will lead to enormous worldwide violence and a war we won’t be able to ignore. The end of that war will be the end of radical Islam.