At Yalta,Roosevelt attained his goal in an agreement for a conference on the United Nations to convene in San Francisco,on 25 April 1945.In addition,Stalin accepted the American proposal on the use of the veto in the SecurityCouncil and the number of Soviet states represented in the General Assembly.
The three men agreed that the eastern boundary of Poland was set roughly at the Curzon line of 1919 and restored western Byelorussia and the western Ukraine to the Soviet Union.Stalin promised free elections there within a month on the basis of universal suffrage and the secret ballot.
Germany would be temporarily divided into three zones of occupation,with France invited to become a fourth occupying power.
Stalin promised that the Soviet Union would enter the war against Japan after thefighting ended in Europe.
In a Declaration on Liberated Europe,proposed by Roosevelt,the three governments pledged jointly to assist liberated people in forming temporary governments representing all democratic elements and pledged to free,early elections.
Roosevelt probably hoped that in the United States,the Declaration would project an acceptable image of the Yalta Conference as the protector of the rights of liberated peoples.It could also be a standard against which Stalin\\u0027s policies in Eastern Europe could be judged.However,Declaration proved ineffective.After the Yalta Conference,the Western powers accepted a Polish government in which two-thirds of the members were Communists.When electionsfinally came in 1947，they were not democratic.
In the Far East,Soviet armies went to war against Japan two days after the atomic bomb was dropped on Hiroshima.The Soviet entry into the war accelerated the Japanese surrender.However,in February 1945，American military planners had expected the war against Japan to drag on into 1946 or even 1947.
As the Cold War heated up,anti-Communist American critics,particularly in the Republican Party,condemned Yalta as a symbol of appeasement and a diplomatic defeat for the United States.Poland and Eastern Europe had been betrayed.The United States should avoid negotiating with the Soviet Union.Some critics later insisted that China had gone Communist because of the YaltaConference.
The reality of Yalta was that the location of armies determined the final outcome.Soviet armed forces decided the politics of Eastern Europe；Allied forces influenced politics in Western Europe.Yalta was an attempt to transform a temporary wartime coalition into a permanent agency for peace.Roosevelt apparently hoped to modify Stalin\\u0027s behavior through the United Nations and postwar U.S.policies.Agreements had been negotiated while war was in progress when unity was vital.After the enemies were vanquished,however,the victors quarreled and their fundamental disagreements emerged.
雅爾塔會議又稱為“克裏米亞會議”，是美國、英國和蘇聯三個大國的政府首腦——富蘭克林·德拉諾·羅斯福、溫斯頓·丘吉爾和約瑟夫·斯大林在1945年2月4日至2月11日之間舉行的一次首腦會議他們各自的參會的目的是討論歐洲戰後秩序問題。這次會議主要側重於討論遭到戰爭嚴重破壞的歐洲的重建。
雅爾塔會議在臨近克裏米亞雅爾塔的利瓦吉亞宮中舉行，這是戰時三巨頭：丘吉爾、羅斯福和斯大林共同出席的會議。這次會議是繼1943年的德黑蘭會議後的第二次同盟國首腦會議。雅爾塔會議召開於波茨坦會議前，在波茨坦會議中，杜魯門代替羅斯福出席。
1945年4月25日，羅斯福在雅爾塔會議上達到了在美國舊金山會議上達成的關於創設聯合國的目的。另外，斯大林接受了美國關於安全理事會否決權的使用和蘇聯的加盟國在聯合國大會中的席位問題。
三巨頭同意將波蘭的東部邊界西移到1919年的寇鬆線，將白俄羅斯和烏克蘭並入蘇聯。斯大林承諾一個月內在波蘭基於普選和秘密投票的原則進行自由選舉。
德國將會暫時的分為三個不同的占領區，法國將被邀請成為第四個占領區。
斯大林承諾在歐戰結束後發動對日戰爭。
在羅斯福提出的關於《自由歐洲的宣言》中，三國政府保證在形成自由民主的臨時政府的過程中解放人民，盡早進行選舉。
羅斯福很可能希望美國在雅爾塔會議中提出的宣言成為自由人民權利的象征。它還可以是反對斯大林東歐政策的評判標準。然而，宣言被證明是無效的。在雅爾塔會議結束後，西方國家接受了一個2\/3成員都是共產黨的波蘭政府。1947年不民主的波蘭選舉結束。
在遠東，蘇軍在廣島原子彈爆炸兩天後開始了對日戰爭。蘇軍參戰加快了日本的投降進程。然而，在1945年2月，美軍顧問預測對日戰爭會遲至1946年甚至1947年結束。
在冷戰的白熱化時期，美國的反共批評者指出，特別是共和黨，譴責雅爾塔會議是綏靖政策和美國外交失敗的象征。波蘭和東歐被出賣。美國應該避免與蘇聯媾和。
雅爾塔會議的實質是軍事力量相較量的結果：蘇軍決定了東歐的政局，而盟軍影響了西歐的政治。雅爾塔會議是將戰時短期聯盟轉化為永久和平機構的一次嚐試。羅斯福明顯想通過聯合國和戰後美國的政策來約束斯大林的舉動。在二戰中時，協議就簽署了。然而，在敵人被消滅之後，勝利者卻陷於爭吵之中，他們基本的分歧顯現了出來。