In July 1945, FBI director J. Edgar Hoover instructed his agents to begin gathering information on CPUSA members to support an analysis of the Party's subversive goals, leading to a 1,850-page report published in 1946 which outlined a case for prosecution.
As the Cold War continued to intensify in 1947, Congress held a hearing at which the Hollywood Ten refused to testify about alleged involvement with the CPUSA, leading to their convictions for contempt of Congress in early 1948.
The same year, Hoover instructed the Department of Justice to bring charges against the CPUSA leaders with the intention of rendering the Party ineffective.
John McGohey, a federal prosecutor from the Southern District of New York, was given the lead role in prosecuting the case and charged twelve leaders of the CPUSA with violations of the Smith Act.
The specific charges against the defendants were first, that they conspired to overthrow the US government by violent means, and second, that they belonged to an organization that advocated the violent overthrow of the government.
The indictment, issued on June 29, 1948, asserted that the CPUSA had been in violation of the Smith Act since July 1945.
 The twelve defendants, arrested in late July 1948, were all members of the National Board of the CPUSA:
Benjamin J. Davis, Jr.  – Chairman of the CPUSA's Legislative Committee and Council-member of New York City
Eugene Dennis – CPUSA General Secretary
William Z. Foster – CPUSA National Secretary (indicted; but not tried due to illness)
John Gates – Leader of the Young Communist League
Gil Green – Member of the National Board (represented by A.J. Isserman)
Gus Hall – Member of the CPUSA National Board
Irving Potash – Furriers Union official
Jack Stachel – Editor of the Daily Worker
Robert G. Thompson – Lead of the New York branch of CPUSA
John Williamson – Member of the CPUSA Central Committee (represented by A.J. Isserman)
Henry Winston – Member of the CPUSA National Board
Carl Winter  – Lead of the Michigan branch of CPUSA
Hoover hoped that all 55 members of the CPUSA's National Committee would be indicted and was disappointed that the prosecutors chose to pursue only twelve.
A week before the arrests, Hoover complained to the Justice Department – recalling the arrests and convictions of over one hundred leaders of the Industrial Workers of the World (IWW) in 1917 – "the IWW was crushed and never revived, similar action at this time would have been as effective against the Communist Party."
In July 1945, FBI director J. Edgar Hoover instructed his agents to begin gathering information on CPUSA members to support an analysis of the Party's subversive goals, leading to a 1,850-page report published in 1946 which outlined a case for prosecution. As the Cold War continued to intensify in 1947, Congress held a hearing at which the Hollywood Ten refused to testify about alleged involvement with the CPUSA, leading to their convictions for contempt of Congress in early 1948. The same year, Hoover instructed the Department of Justice to bring charges against the CPUSA leaders with the intention of rendering the Party ineffective. John McGohey, a federal prosecutor from the Southern District of New York, was given the lead role in prosecuting the case and charged twelve leaders of the CPUSA with violations of the Smith Act. The specific charges against the defendants were first, that they conspired to overthrow the US government by violent means, and second, that they belonged to an organization that advocated the violent overthrow of the government. The indictment, issued on June 29, 1948, asserted that the CPUSA had been in violation of the Smith Act since July 1945.  The twelve defendants, arrested in late July 1948, were all members of the National Board of the CPUSA:
Benjamin J. Davis, Jr.  – Chairman of the CPUSA's Legislative Committee and Council-member of New York City
Eugene Dennis – CPUSA General Secretary
William Z. Foster – CPUSA National Secretary (indicted; but not tried due to illness)
John Gates – Leader of the Young Communist League
Gil Green – Member of the National Board (represented by A.J. Isserman)
Gus Hall – Member of the CPUSA National Board
Irving Potash – Furriers Union official
Jack Stachel – Editor of the Daily Worker
Robert G. Thompson – Lead of the New York branch of CPUSA
John Williamson – Member of the CPUSA Central Committee (represented by A.J. Isserman)
Henry Winston – Member of the CPUSA National Board
Carl Winter  – Lead of the Michigan branch of CPUSA
Hoover hoped that all 55 members of the CPUSA's National Committee would be indicted and was disappointed that the prosecutors chose to pursue only twelve. A week before the arrests, Hoover complained to the Justice Department – recalling the arrests and convictions of over one hundred leaders of the Industrial Workers of the World (IWW) in 1917 – "the IWW was crushed and never revived, similar action at this time would have been as effective against the Communist Party."
Smith Act trials of Communist Party leaders