Along toward the end of World War II, there were rumblings that the powerful IPR might be a communist front, despite its respectable façade–despite the fact that a great majority of its members were Americans whose patriotism and integrity were beyond question.
In 1951, the Senate Internal Security Subcommittee, under the chairmanship of the late Pat McCarran (Democrat, Nevada) began an investigation which lasted many months and became the most important, careful, and productive investigation ever conducted by a committee of Congress.
The McCarran investigation of the IPR was predicated on the assumption that United States diplomacy had never suffered a more disastrous defeat than in its failure to avert the communist conquest of China.
The communist conquest of China led to the Korean war; and the tragic mishandling of this war on the part of Washington and United Nations officialdom destroyed American prestige throughout Asia, and built Chinese communist military power into a menacing colossus.
The Senate investigation revealed that the American policy decisions which produced these disastrous consequences were made by IPR officials who were traitors, or under the influence of traitors, whose allegiance lay in Moscow.
Owen Lattimore, guiding light of the IPR during its most important years (and also a member of the Council on Foreign Relations), was termed a conscious articulate instrument of the Soviet international conspiracy.
Alger Hiss (a CFR member who was later identified as a Soviet spy) was closely tied in with the IPR during his long and influential career in government service. Hiss became a trustee of the IPR after his resignation from the State Department. The secret information which Hiss delivered to a Soviet spy ring in the 1930's kept the Soviets apprised of American activity in the Far East.
Lauchlin Currie (also a member of the CFR) was an administrative assistant to President Roosevelt. Harry Dexter White virtually ran the Treasury Department under both Roosevelt and Truman. Both Currie and White had strong connections with the IPR; and both were Soviet spies–who not only channeled important American secrets to Soviet military intelligence, but also influenced and formulated American policies to suit the Soviets.
By the time the McCarran investigation ended, the whole nation knew that the IPR was, as the McCarran committee had characterized it, a transmission belt for Soviet propaganda in the United States.