Ah... the millenium-old 'anarchy and civil war if we leave' conjecture. After thousands of years, people are still falling for that. Amazing.
Steve: Wasn't trying the millenium-old 'take it out of context and use it' technique either...

Hasn't almost all terrorism against the U.S. been perpetrated by Saudi, UAE and other nationalities though? Since the war against Iraq started, I suppose the combatants in Iraq would have to be called guerilla fighters. But, the semantics are not a big deal. If we get out soon, we'll have less people shooting at our troops sooner, is my point. The mission is over - Saddam is gone.
There will always be people who misunderstand the purpose of another country invading their country. And those who resent being occcupied, no matter how good the intentions of most of the occupiers. Every future unfortunate incident where someone feels unjustly wronged by the bad apples (and there are more bad apples out there) will fuel more resentment and breed terrorists seeking revenge.
I think the U.S. has some bigger fish to fry than Iraq.