A revisionist notion that has never gotten any serious traction, no matter how fervently the children of the 1930s isolationists keep putting it on the table, is the one arguing that America entered World War II under false pretenses. The argument isn’t that the attack on Pearl Harbor didn’t take place — a whopper of that magnitude would have to await the historic breakthroughs in human credulity that have given us a staged moon landing and 9/11 as an American plot. It’s that — or so they keep insisting — FDR knew about the attack in advance and kept his mouth shut because he wanted us in the war.