Obama's memoir dripped with contempt for modern gotcha politics, for a campaign culture obsessed with substantively irrelevant but supposedly symbolic gaffes like John Kerry ordering Swiss cheese or Al Gore sighing or George H.W. Bush checking his watch or Michael Dukakis looking dorky in a tank. "What's troubling is the gap between the magnitude of our challenges and the smallness of our politics—the ease with which we are distracted by the petty and trivial," he wrote.Last night at the National Constitution Center, at a Democratic debate that was hyped by ABC as a discussion of serious constitutional issues, America got...