Many people, including some conservatives, have been very impressed with how brainy the president and his advisers are. But that is not quite as reassuring as it might seem. It was, after all, Franklin D. Roosevelt's brilliant "Brains Trust" advisers whose policies are now increasingly recognized as having prolonged the Great Depression of the 1930s, while claiming credit for ending it. The Great Depression ended only when World War II put an end to many New Deal policies. FDR himself said that "Dr. New Deal" had been replaced by "Dr. Win-the-War." But those today who are for big spending like...