The hope of the organizers of Saturday's "One America" rally in Washington was that a big turnout -- something on par with the crowd Glenn Beck and Sarah Palin attracted at the end of August -- would alter the media's midterm campaign narrative, which to date has emphasized the energy of the Republican base and the likelihood of sizable GOP gains in November. And, to the organizers' credit, the turnout, to the extent it could really be measured, seemed impressive enough. But while we might want to take this as proof that the "enthusiasm gap" is vanishing and that the...