As I remember it, he was a civilian leader of the British Navy during WW-I and even at that time, he schemed to get America into the war on behalf of Britain. Then, as you know, WW-II unspooled in phases. Germany had no interest in getting America involved in the war and tried hard to not anger America. To that end, the German U-Boat fleet was keeping a keen eye on SLOC in the Atlantic and avoided attacking American vessels. And FDR was of the mind of non-interference in the affairs of Europe to the extent possible. So Churchill played underhanded tactics and got American merchant marine targeted as the war carried on, in an effort to get America involved. And as you know, America finally got into the war after it was attacked by Japan in the Pacific.