That’s pretty inaccurate about Truman not knowing anything about the war. He was up to his eyeballs in all the background work that it took to build our bases, build our aircraft, build our ships erc. Fought relentlessly against Fraud and Abuse and waste that was a very real enemy.
He had some involvement here, but not secret stuff, and overseas stuff. FDR had him completely cut out. He had to take a crash course when he FDR died. FDR’s daughter knew far more.