The Bush administration last week reached tentative agreement with Iraq on a phased withdrawal of troops.

The deal calls for U.S. forces to be withdrawn from Iraq’s cities by next June and to leave the country by 2011, nearly eight years after the invasion to oust Saddam Hussein.

Reports out of Baghdad stress that the agreement must still be ratified by the government of Iraqi Prime Minister Nouri al-Maliki and the Bush administration, which in the latter case is formality.

A public announced date for withdrawal was made possible by the success of the “surge,” a beefed up U.S. military presence and the deployment of troops out of large, fixed bases and into the neighborhoods. By chance, the U.S.-Iraq agreement comes as the architect of the surge, Gen. David Petraeus, who has served a total of 48 months in Iraq, prepares to leave to become the top commander of all U.S. forces in the Mideast, North Africa and Afghanistan.

In interviews as he prepares to leave, Petraeus was guardedly optimistic about the security situation and the ability of the Iraqi army to take over from the Americans but, he told one reporter, no one yet is “giving each other high fives.”

If the schedule holds, those will come in two years and four months.