If the US stops policing the world there will not be a WWIII in the near future in my opinion. Also, the arab nations will not be the cause of the next world war. The fear tactics of the government are blowing many things way out of porportion as to keep us on the war bandwagon, and keep increasing governmental power.
When the world war comes it will be the US and its allies versus China and it's allies esentially. The two economic powers of the world which run under completely different forms of government - fighting for limited resources.
Also, I am sick and tired of hearing the word "terrorist." It's a crock of shit, plain and simple. The term has been created in an attempt to make us all run in fear. Religious fundamentalists killing in the name of a higher being has been common since the creation of organized religion, and will always be around. It is not a previously unpronounced variable that is going to screw up the balance of the world and cause mass destruction.