Alright.
If we pull out, civil war is inevitable, even though it is already happening to some extent right now. It will only get worse. Then, while the Sunni's and Shiite's are gunning each other down as soon as we leave, Iran is going to come along to support the (Shiites, i believe they support). So then Iran will be the ruling force because they will obviously defeat the Sunnis, putting them THAT much CLOSER to Israel, who they are determined to blow the shit out of. Basically, if we leave, its disaster. Its Vietnam all over, except this time its not so isolated...the middle east has so much tension leaving now would just leave them in total chaos.