If you’re going to make a documentary film about America’s response to the Holocaust, shouldn’t you at least know how many Jewish refugees were admitted to the United States during those years? Surprisingly, filmmaker Ken Burns appears to be unaware of that basic information—or is for some reason seeking to misrepresent the facts. Burns has announced that his forthcoming film will challenge the “myth” that President Franklin D. Roosevelt abandoned Europe’s Jews. That remarkable assertion flies in the face of the historical record that numerous scholars have thoroughly documented. Nonetheless, in recent interviews, Burns has claimed that during the Roosevelt...