this may be more suited for mayberry, idk. which world leader do you think did the most for his side during world war 2? who made the best decisions with what he had to use? who turned the war in their favor? i am going with churchill. he stopped nazi germany in the battle of britain when it was only him against the axis powers. without his spy service's deception, the d-day invasion may have been repelled. his double agents worked for years to fool hitler about the location of the invasion. agent zigzag. operation mincemeat. broke the nazi code. did numerous things to pull the US into the war. here is a decent documentary about the british secret service during the war if youre interested.