The Washington Times notes that
Given that State Department officer Alger Hiss was with the U.S. delegation, in a relatively minor role, suspicions have long lingered as to whether he had a hand in the concessions FDR made to Stalin. Based on the Soviet documents Mr. Plokhy obtained, the answer is “no.” Stalin, et al., seemed not even aware of Hiss.One explanation is that Hiss spied for the GRU, the intelligence service of the Red Army, whereas Yalta was under the purview of its rival, the NKVD.S.M. Plokhy, a Harvard historian, is clear that Alger Hiss was a Soviet agent, but also that he probably had little or nothing to do with FDR's willingness to yield to Stalin's demands. Hiss was certainly guilty of undermining the U.S. government in various other situations, but not at Yalta. It turns out that there were other Soviet spies among the allied powers:
But intelligence gave the Soviets a clear advantage at Yalta. The infamous Cambridge Five spy ring - think Kim Philby - sent to Moscow papers concerning the British-American positions on Poland.The British traitor-diplomat Donald Maclean, stationed in Washington, kept Moscow apprised of U.S. bargaining strategies. As Mr. Plokhy writes, “His documents were often considered so important and time-sensitive that instead of being sent to Moscow by diplomatic mail they were coded and dispatched by cable.”The Soviet agents kept their activities going long after Yalta, and these activities were not limited to destabilizing western democracies, and thereby endangering their freedoms: the activities included re-writing history:
The Soviet documents revealed a good deal of “rewriting of history,” always to Stalin’s advantage. For instance, although at Yalta Stalin was a staunch advocate of “dismemberment” of Germany after the war, he assigned blame to the West, not wishing to rile his East German subjects.Initially enthusiastic about cooperation of the allied powers at Yalta (and at the other conferences, as well), American diplomats soon began to realize that they had been tricked:
Most of the American delegation left Yalta in exuberant moods. FDR confidant Harry Hopkins spoke of the “dawn of a new age we had all been praying for and talking about for so many years.” Secretary of State Edward Stettinius claimed that the Soviets “made greater concessions” than did the United States or Britain.The Yalta conference, which could have laid the foundation for world peace and the expansion of international democratic liberties, instead was another step on the road toward the Cold War, and toward Stalin's domination of the war-ravaged nations in eastern Europe.
But a few months later, Averell Harriman, who had served as ambassador to Moscow, bluntly warned the new president, Harry S. Truman, that “Stalin is breaking his agreements,” and that there was a new “barbarian invasion of Europe.”