Since losing the most winnable presidential election in modern American history, Hillary Clinton has, among other things: given a series of high-profile speeches, joined Gov. Cuomo at his public unveiling of tuition-free college, refused to rule out a run for mayor of New York and issued an online video message exhorting fellow Democrats to fight on in her name. “The challenges we face,” she said, “as a country and a party, are real.” Clearly, Hillary still sees herself as the leader of the Democratic Party. And why shouldn’t she? Democrats have been locked in an abusive relationship with the Clintons...