One big fact has largely been lost in the recent coverage of the Democratic presidential race: Hillary Rodham Clinton has virtually no chance of winning. Her own campaign acknowledges there is no way that she will finish ahead in pledged delegates. That means the only way she wins is if Democratic superdelegates are ready to risk a backlash of historic proportions from the party’s most reliable constituency. Unless Clinton is able to at least win the primary popular vote — which also would take nothing less than an electoral miracle — and use that achievement to pressure superdelegates, she has...