Every decade or so, the Pew Research Center sorts the American electorate into discrete groupings with interesting names.    By E.J. Dionne, Jr. truthdig.com  June 30, 2014 Dirk Loop (CC-BY) Here’s one political paradox: A substantial majority of Americans do not fit neatly into the conventional “liberal” and “conservative” boxes, yet there is no coherent political center. Those More