Biography
Max Eastman was a poet, journalist, and the editor of The Masses, the radical New York socialist literary magazine that published Carl Sandburg, John Reed, Floyd Dell, and the cartoons of Art Young between 1911 and 1917. After the United States entered World War I, the Post Office revoked The Masses' second-class mailing privileges under the Espionage Act of 1917, effectively shutting it down. Federal prosecutors then indicted Eastman, John Reed, Floyd Dell, Art Young, and the magazine's business manager Merrill Rogers in November 1917 for conspiracy to obstruct military recruitment. The first trial in April 1918 ended in a hung jury; the second in October 1918 also ended in a hung jury. Federal prosecutors declined to bring a third prosecution, and the charges were dismissed. Eastman went on to launch The Liberator as the successor magazine and remained a prominent radical voice through the 1920s.
Socialist Call, January 16, 1937, page 4: In criticizing the New Masses' refusal of a Debs Column advertisement, the editorial recalls Max Eastman facing trial in connection with the original Masses during World War I. It specifically recalls Young caricaturing himself asleep during court proceedings. This is retrospective corroboration of the existing antiwar-publication prosecution, not a new detention or a measured imprisonment term. Source: https://www.marxists.org/history/usa/pubs/socialist-call/call%202-96.pdf
The January 1919 Liberator recounts a December 8 Cleveland raid in which five unnamed people were jailed. It says Eastman escaped to Buffalo. This is personal reporting about the raid, not evidence that Eastman himself was among those five detained people. Source: https://www.marxists.org/history/usa/culture/pubs/liberator/1919/01/v2n01-w11-jan-1919-liberator.pdf#page=50