Correct me if I am wrong, but I would view him as being successful as a cheerleader, for lack of a better word and international diplomat. He seemed to me (having not lived at the time) to be a motivator. I also think his personal friendship with Roosevelt was not something to be taken lightly. It certainly had to figure heavily into many of the decisions made on this side of the ocean in regards to playing fast and loose with neutrality. I don't see the US coming in on the side of the Axis but how much longer would it have taken if we were not already intertwined in the Atlantic convoys and other war aid? If the US was staying strictly neutral, would Adolf Hitler have jumped on a quick declaration of war following Pearl Harbor? Whether we like it or not, there was a strong isolationist and anti-British sentiment in the US. Roosevelt had a devil of time getting what aid and preparations he could past the House and Senate. If Churchill and Roosevelt had been at odds with each other, would Roosevelt have been as willing to stick his political neck out for the UK? We will probably never know, Roosevelt could very well have been anti-Nazi enough that it did not matter about the leadership of the British Isles, he was going to fight Germany anyway. Having Churchill as the PM during the war may have just made it all the more easier.