Obama is the challenger tonight on foreign policy, the younger man who has to win enough trust to be considered credible. McCain is the experienced incumbent, who only has to argue his many years and many decisions. McCain delivered his bit. His problem was that Obama did also. He seemed more than credible enough. It was not hard to imagine him as president. The basic differences were clear: McCain would be more bold, more aggressive, more confident, whereas Obama would be more cautious, more careful, more selective. That much is clear. But a draw for Obama is a loss for McCain tonight. Obama got what he needed--the image in his supporters' minds and among enough of the undecideds that this guy can indeed be commander-in-chief. McCain needed a knockout, because, as the economy proved this week, the following debates will be hard for him, as will the campaign.