First, that's what polls in Iraq show

Second, that's also what americans want.

Third, the insurgents will stop their fight against the occupants.

Fourth, the Iraqis will see this as a victory for all of them and this couldl unite them.

Fith, there's that argument: the US gone,there will be a genocide....How? Who? The Sunnis against the Shi-ites? One forgets Saddam is no more in power and Iran is right next doors. Plus the fact there's an army. Even if there were a sudden change of power (because power vacancy doens't exist), the army will follow whoever is in charge. There have been plenty of Coups d'Etat without genocide following. There will likely be a strongman (not the one chosen by the US) and a surge in violence is possible but not for long. No country can bear so much more violence and the army will have to bring back order, no matter who's in charge.

Sixth, this will all be done with the eyes of the world looking...not just Fox news but also Al Jazeera.

Seventh, the US point of view is very different: it's about the necessary admittance this war cannot be won therefore is lost), nor should it have happened in the first place (terrorism is not fought with soldiers and tankers and bombers, but secretly, by infiltrations, information sharing..etc).

When americans argue they must stay "until the time is ready", I'm sure they think a lot more about what it would entail to their own pride than what it would mean to the Iraqis.