While commemorating the 250th anniversary of the US over the weekend, President Donald Trump made a speech that echoed a bygone era. “Communism is a mortal threat to American liberty,” he said at a July 3 semiquincentennial event at Mount Rushmore. “It is the greatest threat to our country, including World War I, World War II, Pearl Harbor or even 9/11.” It was one of 14 “communism” or “communist” mentions in a speech spanning 30 minutes. The next day, at a Fourth of July celebration on the National Mall, the president again devoted considerable time to warning about the specter...