Remember when Joseph Stalin was familiarly known as "Uncle Joe" in the chief western allies (the United Kingdom and the United States). Uncle Joe was on our side in the battle to defeat the Third Reich.
Few will remember that the Russian Soviet Socialist Republic's military forces were supplied with huge amounts of American military materials for the fight.
Uncle Joe was on our side, but Joseph Stalin had grimmer and more devious plans for a "Soviet Empire" which in due course led to the economic and political slavery of such countries as Poland, Czechoslovakia, Hungary, Latvia, Lithuania, Estonia etc, from 1945 - 1991.
Uncle Joe was wily. Churchill and Roosevelt were naive.
Churchill had an over abundance of confidence in his skills as a military strategist and a political negotiator.
Roosevelt was physically exhausted and weary. By February 1945 he was close to death.
There were two major war time conferences between Stalin, Churchill and Roosevelt in the WW 2 era.
Tehran 1943 at which Churchill agreed to open a western front in the fight against Hitler leading to "Operation Overlord" in 1944. The Russians invented a Nazi plot to assassinate Stalin, Churchill and Roosevelt in Tehran and persuaded FDR to move into their Embassy - just where they could spy in him!)
Yalta Feb 1945 (ironically Yalta is in Crimea), where the sick and weary Roosevelt and the over confident and brash Churchill agreed to the post war division of Europe.
Later in 1945 there was the Potsdam Conference. Stalin was the ever present Svengali . Roosevelt had died, Harry Truman was now the USA President. The U.K. was at first represented by Churchill bur following his defeat in the 1945 General Election his place was taken by the new U.K. Premier, Clement Attlee.
Postdam led to the ultimate western betrayal of Poland (and that's a story in its own right). Uncle Joe won.
Dear readers I am not a historian nor have I had advanced studies in history.
Bear that in mind as I ask: "if Roosevelt and Churchill were so mistaken in their beliefs that a charm offensive would tame Uncle Joe what would lead us to believe that the willfully ill prepared Donald Trump will charm Putin in their one on one in Helsinki?"
If President Trump passively or actively accedes to the Russian annexation of the Crimea then the leaders of the Ukraine, Estonia, Latvia and Lithuania will have abundant reason to fear the Russian Bear.
Here are some quotations from Wikipedia re Yalta etc
(1) Roosevelt conceded that, in the words of Admiral William D. Leahy, the language of Yalta was so vague that the Soviets would be able to "stretch it all the way from Yalta to Washington without ever technically breaking it."
(2) By March 21, Roosevelt's Ambassador to the USSR Averell Harriman cabled Roosevelt that "we must come clearly to realize that the Soviet program is the establishment of totalitarianism, ending personal liberty and democracy as we know it." Two days later, Roosevelt began to admit that his view of Stalin had been excessively optimistic and that "Averell is right."
(3) Roosevelt had brushed off warnings of a potential domination by a Stalin dictatorship in part of Europe. He explained that "I just have a hunch that Stalin is not that kind of a man" and reasoned, "I think that if I give him everything I possibly can and ask for nothing from him in return, 'noblesse oblige', he won't try to annex anything and will work with me for a world of democracy and peace.