These agents had various functions: some gathered intelligence by stealing classified documents; others influenced U.S. policy makers to skew diplomatic decisions to the advantage of the USSR; and some actually prepared for an overthrow of the U.S. government.
Such spies were coordinated, in part, through the Communist Party, which was in fact not a political party, not interested in merely advocating policies and candidates, but which was actually a terrorist organization, explicitly advocating a “violent” revolution in North America. As historians Stan Evans and Herbert Romerstein write,
In due course many such pro-Soviet operatives rose to fairly high positions, which made their allegiance to Moscow even more problematic. The best known of these apparatchiks was Alger Hiss, who became a significant figure in the U.S. State Department in the war years and would play a critical role in planning for the postwar era. And while Hiss is the most remembered of Moscow’s undercover agents, he was merely one of many. As the records prove, there were dozens of others like him at the State Department, White House, Treasury, Commerce, the wartime agencies, and other official venues.
By 1943, President Roosevelt’s failing health caused him to be increasingly reliant on assistants, instead of formulating his own policy decisions by himself.
Documents declassified after the end of the Cold War verify that Alger Hiss was a Soviet agent. Hiss was one of FDR’s trusted advisors, having considerable influence on Roosevelt’s policies during face-to-face meetings with the president.