Aside from a ten-day period in June and early July of 1941 where he had a paralysing nervous breakdown during the openning moves of Operation Barbarossa, the greatest leader of WWII was Joseph Stalin, as his personal force of will and bloody-minded purpose allowed him and the Soviet Red Army to slow, stop, and grind up the German and wider European fascist forces which had invaded the USSR. It was Stalin's Red Army which did by far the most damage to the fascist militaries arrayed against the Allies. It also secured Eastern Europe for the Soviet Empire's hegemony until the 1990's. Stalin was a monster but it is hard to argue that he wasn't the greatest leader of that period. Please do not confuse my use of "great" with the idea that he was a "good" leader. He wasn't. Morality and efficiency were almost entirely lacking from his repetoire of skills. But he was victorious despite immense challenges and under his leadership the Soviet Union came out as one of the big winners of the war, despite the appaling death toll and destruction which approached forty million Soviets, Ukrainians and Balts dead.
While not grammatically sound, the "goodest" leader of the war was likely Franklin Roosevelt and following him Harry Truman (who might have been "gooder" if his wartime tenure had not been so short). These men piloted their country through a global, total war while generally preserving the institutions of American freedom and liberty to which they had sworn an oath to preserve. They had lapses like the dreadful abuse of Americans of Japanese descent being interned or the human medical experimentation on African-Americans at Tuskeegee, but generally they managed to preserve American liberty through this brutal, existential struggle of the 1940's. They forged the US-dominated "Grand Area", which, with the exception of the loss of China in 1949, has remained intact into the 21rst Century, as a defacto invisible empire which appears on no map, but which has enriched America greatly.
The worst leaders of the war were Hitler and Mussolini who destroyed their own countries and bathed Europe in the blood of millions for their blind ambition and selfish vain-glory. Hirohito was an anachronism who did not really belong in the 20th Century but Tojo was the real villain and takes his place beside Hitler and Mussolini as a self destructive fool of the highest order.
Churchill was the sneakiest and most calculating of the lot and was planning a Third World War with the Soviets when the sensible British electorate ran him out of office as unfit for peacetime leadership. Neville Chamberlain was as foolish as the Axis leaders for his reciprocal belief that "peace in our time" at all costs would work with such predatory men like Hitler, Mussolini and Stalin in the political mix. And then there's the French. N'uff said.
Cheers.
Evilroddy.
