According to the diaries of Edward Stettinius Jr., the secretary of state at the time of Yalta, President Roosevelt in the run-up to the meeting made some peculiar comments about the people he thought should be there.
Roosevelt was, on the one hand, oddly indifferent to the selection of the staff he would take with him to Yalta; on the other hand, he was oddly specific about naming one or two individuals whom he wanted to be part of that group.
At a White House briefing a month before the conference opened, Settinius wrote, FDR said he wasn't overly concerned about having any particular staffers with him at Yalta, but qualified this with two exceptions. "The President," said Stettinius, "did not want to have anyone accompany him in an advisory capacity, but he felt that Messers. Bowman and Alger Hiss ought to go." No clue was provided by Stettinius, or apparently by FDR himself, as to the reason for these choices.
Who were these two men, named by Roosevelt and desired by him to accompany him to Yalta? Bowman, as far as history can tell, is a seemingly unremarkable, if competent and successful, diplomat. He had an established and accomplished career, even if the average newspaper reader wouldn't recognize the name of
Dr. Isaiah Bowman of Johns Hopkins University, who had been involved in the Versailles conference after World War I and was a Stettinius advisor. He did not go to Yalta, though Alger Hiss would do so.
Alger Hiss, on the other hand, would become a notorious name in history books. His career consisted of directing top level government secrets from Washington to Stalin's government, and of influencing high-level decision-making in FDR's administration: influencing the United States government to make decisions, not in America's best interests, but rather to the advantage of the USSR.
Alger Hiss, it will be recalled, was a secret Communist serving in the wartime State Department, identified as a Soviet agent by ex-Communist Whittaker Chambers, a former espionage courier for Moscow's intelligence bosses. This identification led to a bitter quarrel that divided the nation into conflicting factions and would do so for years to follow. The dispute resulted in the 1950 conviction of Hiss for perjury when he denied the Chambers charges under oath, denials that ran contrary to the evidence then and to an ever-increasing mass of data later.
Like many other aspects of the extensive Soviet spy rings inside the United States during the 1930's, and lasting until the end of the Cold War, details about these operations became more widely known after the fall of the Soviet Union. In the 1990's, masses of KGB files were declassified and released to the west, confirming that Hiss and other high-level officers in the State Department were in fact on the payroll of Soviet intelligence agencies.
Though Hiss is now well-known to history, in January 1945 he was merely one State Department staffer among many, and of fairly junior status - a mid-level employee who wasn't even head of a division (third ranking in the branch where he was working). It thus seems odd that Roosevelt would single him out as someone who should go to Yalta - the more curious as it's reasonably clear that FDR had never dealt with Hiss directly (a point confirmed by Hiss in his own memoirs).
What caused FDR's odd choice? We will probably never know. He would die that April; his health was certainly declining. He would be replaced by President Truman, who, like Churchill, saw through Stalin's promises. Truman would not be deceived by the Soviet dictator, and during the Truman administration, security reviews of State Department employees would begin to both uncover existing spies, and prevent the infiltration of additional Soviet agents.