Nancy Pelosi might actually be in trouble. In a survey of 20 Democratic House candidates, only one – a former Senate staffer from Orange County, California – would state support for the congresswoman staying on as leader of the House Democratic Caucus. Of the rest, 18 declined to say if Pelosi should keep her job, while one, a political newcomer from a culturally conservative Ohio district, said he would vote for someone other than Pelosi. Their refusal is a remarkable development for an already embattled minority leader. Democrats are eager to win a majority buoyed by voters’ disapproval of President...