I try not to be part of the blogosphere echo-chamber, but I think it's important people get what Josh Marshall is saying here:
There's nothing odd or contradictory about Obama saying that he'll change the policy to one of withdrawal of American combat troops from Iraq with a specific timetable but that he will consult with his military advisors about how best to execute that policy.
The simple truth is that this campaign offers a very clear cut choice on Iraq. One candidate believes that the US occupation of Iraq is the solution; the other thinks it's the problem. John McCain supports the permanent deployment of US troops in Iraq. That is why his hundred years remark isn't some gotcha line. It's a clear statement of his policy. Obama supports a deliberate and orderly withdrawal of US forces from Iraq. It's a completely different view of America's role in the world and future in the Middle East.