John McCain has begun vigorously engaging Barack Obama on the subject of Obama’s proposed immediate withdrawal of U.S. troops from Iraq. As reported by abcnews.com, he got a major assist yesterday from the Chairman of the Joint Chiefs who stated that:

[a] rapid of withdrawal from Iraq would lead to a “chaotic situation” and would “turnaround the gains we have achieved, and struggled to achieve, and turn them around overnight. Admiral Mullen’s comments came in a response to a question about what the Joint Chiefs are doing to prepare for a new president, given that two of the candidates have called for a timetable for withdrawal from Iraq. “We need to be prepared across the board for what a new president will bring,” Mullen said. “I do worry about a rapid withdrawal. . . [that would] turn around the gains we have achieved and struggled to achieve and turn them around overnight.” Asked to define a “rapid withdrawal,” Mullen said, “a withdrawal that would be so fast that it would leave us in a chaotic situation and the gains we have achieved would be lost.” That said, Mullen added: “When a new president comes in, I will get my orders and I will carry them out.”

Obama would certainly like to talk in the general election about the initial decision to go to war, which has been a winning issue in his primary fight with Hillary Clinton. In light of polling which shows a lopsided majority of Americans believe that the war was a mistake or not worth the cost, this seems a smart tactic. McCain intends to cast this, in essence, as crying over spilt milk. As he put it “That’s history, that’s the past. . . . What we should be talking about is what we are going to do now.”

Indeed the “what do we do now” issue was much discussed in the last presidential election year. Back then, when Colin Powell subscribed to the “pottery barn” analogy (you break it, you pay for it), he was widely praised. Democrats had no problem when John Kerry said this in the 2004 presidential debate:

Yes, we have to be steadfast and resolved, and I am. And I will succeed for those troops, now that we’re there. We have to succeed. We can’t leave a failed Iraq. But that doesn’t mean it wasn’t a mistake of judgment to go there and take the focus off of Osama bin Laden. It was. Now, we can succeed.

For Obama and much of the Democratic base, that was then and this is now. Meanwhile, McCain hopes that the adage that “elections are about the future and not the past” holds true here.