Here's Obama's response to the Iraq deal:

I am glad that the Administration has finally shifted to accepting a timetable for the removal of our combat troops from Iraq. Success in Iraq depends on an Iraqi government that is reconciling its differences and taking responsibility for its future, and a timetable is the best way to press the Iraqis to do just that. I welcome the growing convergence around this pragmatic and responsible position.

That's the jab. And now the K.O. punch:

"Senator McCain has stubbornly focused on maintaining an indefinite U.S presence in Iraq, but events have made his bluster and record increasingly out of touch with reality. While Senator McCain continues to offer unconditional military and economic support for Iraq, I strongly believe that we need to use our leverage with the Iraqi government to ensure a political settlement. In addition to a timetable, we should only train Iraqi Security Forces if Iraq's leaders reconcile their differences, and we must insist that Iraq invests its $79 billion surplus on rebuilding its own country. It's time to succeed in Iraq and to honor the sacrifice of our servicemen and women by leaving Iraq to a sovereign Iraqi government."

That's really pitch-perfect in a variety of respects. First, it makes the point that the administration came around to the wisdom of Obama's position after exhausting the alternatives. Second, it portrays Obama's position as the consensus view. Third, it puts McCain on the horns of a dilemma: Either endorse Obama's consensus position -- and thereby flip-flop and concede his opponent's judgment is superior -- or be out of the responsible mainstream. Third-and-a-half, if McCain stays consistent, the Obama line draws a wedge between Bush and McCain.

But there's a fourth reason, and it's the most crucial of all. Did you notice how Obama is talking about "success in Iraq"? He's taking that concept and giving it a common-sense meaning: getting out responsibly -- that is, leveraging withdrawal into a diplomatic strategy with the Iraqi government and the region -- is what success means. That, by the way, isn't just a good campaign strategy. It'll be a good governing strategy, giving the military its due respect from a civilian leader while taking up the arduous and tripwire-laden task of actually withdrawing.