The highest-ranking US general in Iraq has said that the Iraqi Army should be capable of assuming responsibility for the country's security in 12-18 months. According to General George Casey, "I don't have a date, but I can see over the next 12-18 months the Iraqi security forces progressing to a point where they can take on the security responsibilities for the country, with very little coalition support."
No public policy can be successful without clear metrics for success, and this has been one of the critical flaws in President Bush's Iraq strategy. Now, despite the steady and increasing levels of violence in the country, we have some sense of what can and should be expected from the reconstruction process. As far as the US is concerned, many of the political goals have been met: A new government has been formed, a new constitution drafted, elections held. Now it's time to focus on the security goals, the measure of which is when Iraqi forces will supplant US ones in policing and securing the country.
The time line mentioned by Casey jibes with other statements from US military officers in positions to judge these things. It's time for supporters and critics of the war alike to hang their hats on a clear standard: In a year-and-a-half, US soldiers should begin withdrawing from Iraq and turning primary responsibility for security over to the Iraqi Army. If this can't be achieved, even those still supporting the occupation will have to admit failure.