The first military consequence, of course, would be the collapse of all American, international and Iraqi resistance to the terrorist jihadists and the various religiously-inspired militias who are even now slaughtering scores of their fellow Iraqis every day. "Civil war" is almost too dignified a term for the chaos into which Iraq would collapse. Eventually, various poles of political authority would emerge, no doubt supported financially and militarily by the various Islamic nations on Iraq's borders. These nations in turn, freed from any obligation to honor such concepts as "democracy" or even "liberty," would impose even worse tyrannies than those existing today on their own peoples, and the Middle East would become one vast cesspool of Islamic dictatorships, bent on expansion.
Worse yet, America's reputation as a defender of freedom, let alone an honorable and formidable military power, would turn to mud. The terrorists, triumphant over having forced Uncle Sam to turn tail, would double or triple in size on short order, and train their sights on further terrorist victories in Europe -- and, of course, in the United States. (Or do you think that, gratified by the success of the Pelosi Plan, Osama bin Laden and his allies would call off their jihad against the West and the Great Satan and go back to tending their goats?)
As President Bush has tirelessly reminded us, we didn't start this war, and the attack on Iraq was simply a belated response to a series of Islamist assaults on the West stretching back nearly thirty years. No American soldier was anywhere near Iraq, or even Afghanistan, on 9/11. That was our "Pelosi Plan," and it didn't work.