"Father knuckling under like Roosevelt at Yalta"

Franklin Delano Roosevelt
Public DomainFranklin Delano Roosevelt
 The Yalta Conference of 1945 was a post-war meeting between U.S. President Franklin D. Roosevelt, United Kingdom Prime Minister Winston Churchill and Soviet Union Secretary General Joseph Stalin. 

Stalin was accused of bullying Roosevelt as the men sought to re-organise Europe after the war. Here is an interesting article on the relationship between the two.