The DNC’s “100 years” ad targeting John McCain drew the predictably ire of the Republican Party this week, with McCain allies arguing that McCain doesn’t want to keep the war going through 2108, he’s just willing to leave U.S. troops in Iraq there indefinitely to help maintain the peace.

Now, as I noted the other day, McCain has changed his mind on multiple of occasions about whether this is realistic, but for now, he seems to sincerely believe that Iraqis would not only allow the United States to maintain a Korea-like presence in Iraq for decades to come, but that such a presence is actually necessary.

This strikes me as a pretty ridiculous policy, but let’s take it a step further. McCain is willing to leave troops in Iraq for up to a century after the war ends. Got it. But how long do we keep U.S. troops in Iraq during the war? As it turns out, that’s indefinite, too.

As Ron Brownstein explains, it’s incumbent on McCain to go into more detail.

First, if McCain doesn’t envision a 100-year American front-line combat presence in Iraq, how long is he willing to keep U.S. forces in that role? So far, all he has said is that the United States should withdraw only if it concludes that the Iraq mission is unachievable or when it has achieved success, which he defines as the establishment of “a peaceful, stable, prosperous, democratic state.” […]

McCain has not said when, but he has pledged that Iraqi units will eventually assume the major combat responsibility. That prompts the next question McCain should address: What would then become the mission for the U.S. forces he wants to maintain in Iraq?

McCain hasn’t been able to answer either question. He hasn’t even tried.