Donald Trump's image among the overall U.S. population has trended up, not down, after his Dec. 7 recommendation that the U.S. prevent Muslims from coming into the country. The statement was met with extraordinary controversy -- even for Trump -- and most of his fellow Republican candidates, along with Democratic leaders, denounced it. Clearly, it would not have surprised many observers if Trump's image had taken a hit as a result. But we can reject that hypothesis, at least based on data we have collected so far. Trump had a negative image among American adults to begin with, but it...