As a nervous nation watches the Obama administration’s response to the Ebola crisis, many Americans have concluded that the country’s top health officials seem more concerned with stopping the spread of panic than stopping the spread of the virus. But Americans’ fear is only growing, and one reason is that too few people believe what the president of the United States says anymore. A recent poll asked Americans this question: “How often does Barack Obama lie to the country on important matters?” Not about sex. Not about whether he really likes baseball. Not whether he still cadges an occasional cigarette...