Reality

From the NIE Report:

There have been measurable but uneven improvements in Iraq’s security situation since our last National Intelligence Estimate on Iraq in January 2007. The steep escalation of rates of violence has been checked for now, and overall attack levels across Iraq have fallen during seven of the last nine weeks. Coalition forces, working with Iraqi forces, tribal elements, and some Sunni insurgents, have reduced al-Qa’ida in Iraq’s (AQI) capabilities, restricted its freedom of movement, and denied it grassroots support in some areas. However, the level of overall violence, including attacks on and casualties among civilians, remains high; Iraq’s sectarian groups remain unreconciled; AQI retains the ability to conduct high-profile attacks; and to date, Iraqi political leaders remain unable to govern effectively. There have been modest improvements in economic output, budget execution, and government finances but fundamental structural problems continue to prevent sustained progress in economic growth and living conditions.

We assess, to the extent that Coalition forces continue to conduct robust counterinsurgency operations and mentor and support the Iraqi Security Forces (ISF), that Iraq’s security will continue to improve modestly during the next six to 12 months but that levels of insurgent and sectarian violence will remain high and the Iraqi Government will continue to struggle to achieve national-level political reconciliation and improved governance.

So we're left with continuing the current strategy, which will give us no real gains over the current situation, or leaving, and the civil war that would follow. It seems to me the choice is between an open-ended occupation, hoping with no reason for the best and a prudential withdrawal, expecting with good reason the worst.