The humid lull between the party primaries and the party conventions is the traditional moment for a Presidential challenger to peacock abroad as a prospective Commander-in-Chief. Four years ago, Barack Obama cruised the Iraqi war zone in a helicopter, dazzled throngs in Europe with his then fresh rhetoric of change, and charmed American soldiers in a Kuwaiti gymnasium, where, with preternatural nonchalance, he lofted a three-point shot toward a distant rim. He drained the three, the soldiers roared, and, somewhere back home, John McCain slumped deeper into gloom.