Biden right: No fast way out.

U.S. commanders say it would be a lengthy process, and independent military analysts have said it would take about a year to pull U.S. troops out of Iraq safely. It could be done faster, but with larger U.S. casualties and more abandoned equipment, experts say. McClatchy Newspapers has reported that a simulation conducted by the Pentagon since the debate suggested a retreat could take as little as six months, but critics said that estimate is overly optimistic.

"We must consider the complexity of the threat and deliberately reduce our forces based on the situation on the ground as well as the capability of the Iraqi security forces," Army Lt. Gen. Ray Odierno, the deputy commander of forces in Iraq, said at a briefing this month. "I think the plan will reflect that as we develop it."