Maybe the instincts of a nation who thought invading Iraq and overthrowing Saddam or earlier arming Saddam to fight the Iranians or earlier arming Islamic fanatics to fight the Soviets should not be listened to.

Lebanon and Syria are mixed between Sunnis and Shia and they hate each other and Iraq is dominated by Shia as is Iran. If the USA disenfranchises the Shia in Syria we have a middle eastern inter religious war with Iraq destabilized by Iran and a split Shia portion of Syria and Iraq may fall even deeper into Iran’s orbit. Iran getting involved in a peace process may not be a bad idea.

Maybe you are hoping for some Machiavellian plan to have all these Muslim groups fight each other but wars like that have a tendency to get out of control.