General David Petraeus deployed overwhelming force when he briefed Barack Obama and two other Senators in Baghdad last July. He knew Obama favored a 16-month timetable for the withdrawal of most U.S. troops from Iraq, and he wanted to make the strongest possible case against it. And so, after he had presented an array of maps and charts and PowerPoint slides describing the current situation on the ground in great detail, Petraeus closed with a vigorous plea for "maximum flexibility" going forward. Obama had a choice at that moment. He could thank Petraeus for the briefing and promise to take his views "under advisement." Or he could tell Petraeus what he really thought, a potentially contentious course of action -- especially with a general not used to being confronted. Obama chose to speak his mind. "You know, if I were in your shoes, I would be making the exact same argument," he began. "Your job is to succeed in Iraq on as favorable terms as we can get. But my job as a potential Commander in Chief is to view your counsel and interests through the prism of our overall national security." Obama talked about the deteriorating situation in Afghanistan, the financial costs of the occupation of Iraq, the stress it was putting on the military.