Earl Browder was the General Secretary of the Communist Party of the United States of America (CPUSA) from 1932 to 1945. During World War II, when the United States and Soviet Union were allied fighting Nazi Germany, Browder publicly took the position that Communism and capitalism could coexist, which was the position the Soviet Union had taken during World War II. Browder was removed from leadership in 1945 for deviationism.
Complicity in Soviet espionage and subversion
Browder, as CPUSA General Secretary, long benefited from the denial of the liberal and leftist intelligentsia that the CPUSA did not participate in Soviet espionage against the United States. These assertions continue, despite the presentation of substantial contrary evidence over the years by Elizabeth Bentley and others  the Venona cables, the Judith Coplon, Alger Hiss, and William Remington trials, as well as dozens of articles and books. In the Venona cables he is known as Agent "HELMSMAN".
In 1939 Browder appointed Rudy Baker to head the CPUSA underground apparatus to replace J. Peters, after the defection of Whittaker Chambers. Browder was sentenced to prison in 1940, ostensibly due to passport violations, but was released after 14 months when the US joined World War II and became an ally of the Soviet Union. Browder embraced the Popular Front and led the CPUSA's tactic of expressing cautious support for the New Deal of Franklin Delano Roosevelt while demanding that it should go much further than it did.
During this period Browder successfully recruited dozens of operatives from amongst his associates for Soviet intelligence. An indication of Browder's cooperation with the KGB can be derived from a discussion Jacob Golos had with Browder in November 1943 regarding a group of KGB informants he was running. Browder became involved in the operation, and after Golos's death that same month, Browder arranged with Bentley to take over the Perlo group. She met the members in John Abt's apartment in New York.  Venona decrypt #588 April 29 1944 from the KGB New York office states “for more than a year Zarubin (station chief) and I tried to get in touch with Victor Perlo and Charles Flato. For some reason Browder did not come to the meeting and just decided to put Bentley in touch with the whole group. All occupy responsible positions in Washington, D.C.” 
Earl Browder's close association with the KGB was further borne out by the fact that he was the recipient of classified data. KGB Case Officer Iskhak Akhmerov and Nathan Gregory Silvermaster agreed that Akhmerov would pass intelligence on the Chinese Communist Party to Browder through KGB Rezident Anatoly Gorsky or CPUSA organizational secretary Bernard Schuster. Browder's niece, Helen Lowry was married to Akhmerov and was a KGB spy, too.
As early as May 1943, Browder cabled to Moscow U.S. armament production statistics on tanks, anti-tank guns, machine guns, battleships, aircraft carriers, cruisers, destroyer and merchant vessels. 
Election of 1944
During the Presidential election of 1944, on May 23 at a rally in New York's Madison Square hailing the "Democratic Coalition," Browder announced the birth of the "Communist Political Association," which he described as "a non-party organization of the American working class dedicated to the traditions of Washington, Jefferson, Paine, Jackson and Lincoln, under the changed conditions of modern industrial society." 
In May of 1944 Raissa Browder, Browder's wife who had entered the United States illegally, was permitted to become a citizen. According to the sworn testimony of ex-Communist Howard Rushmore, State Department and Immigration Service officials insisted upon this at the urgent requests of Secretary of State Cordell Hull and Mrs. Eleanor Roosevelt. 
Browder is referenced in
Browderism and Marxist deviationism
In April 1945 Jacques Duclos of the French Communist Party published a repudiation of Browderism. Browder was expelled from the American Politburo in February 1946. Browder at the time held a 5-year contract to represent Soviet publishing houses in the United States which kept him on the payroll for a time.
In a speech delivered on January 17, 1949, which was reprinted as a pamphlet entitled Chinese Lessons for American Marxists, Browder points to this distinctiveness of Chinese Communist Party theory, its “exceptionalism” as the reason for its success. He quotes from several of Anna Louise Strong’s articles in support of his thesis that Mao Tse-tung’s policy has been to develop a particular line for Chinese Communism, to "China-ise Marxism and Leninism." (Page 9.) Browder quotes extensively from The Thought of Mao-Tse-tung by Anna Louise Strong. Browder was purged for just such an exceptionalist approach in the United States.
- John E. Haynes, Red Scare or Red Menace, Chicago: Ivan R. Dee, 1996, p. 61.
- Harvey Klehr, John Earl Haynes, and Fredrikh I. Firsov, The Secret World of American Communism, New Haven: Yale University Press, 1995, p. 233.
- FBI Report, New York #65–14913, 8 November 1950 and 65–57913.
- Venona 588 New York to Moscow 29 April 1944.
- Venona 774, 775, and 776 New York to Moscow 26 May 1943.
- Angela Calomiris, Red Masquerade: Undercover for the FBI, (Philadelphia:Lippincott, 1950), pp. 141-142.
- US Senate, 81st Congress, 1st Session, Committee on the Judicary, Hearings Before the Subcommittee on Immigration and Naturalization, September 14, 1949, Part II, (GPO), p. 785.
- Scope of Soviet activity in the United States. Hearing before the Subcommittee to Investigate the Administration of the Internal Security Act and Other Internal Security Laws of the Committee on the Judiciary, United States Senate, Eighty-fourth Congress, second session-Eighty-fifth Congress, first session. Washington, U.S. Govt. Print. Off. 1956.
- Jack Brad, How Mao Conquered China, Edited by Hal Draper. Compilation originally published in Labor Action between September 1948 and October 1949. Reprinted in Workers Liberty Volume 3 No. 24, October 2009, p. 8 (pdf). Retrieved from WorkersLiberty.org February 23, 2010.