)[1] was a law of California in 1919 under Governor William Stephens criminalizing syndicalism.

Simple advocacy of a certain belief or membership in a group that advocated syndicalism was enough to secure a conviction".

[4] The Act must be viewed in the context of the First Red Scare and the turbulent labor history of the United States in the early 20th century.

[6] Of the hundreds arrested, 16 were charged by the Imperial County Grand Jury with violations of the Criminal Syndicalism Act,[6] and 8 were convicted on 13 June 1930 and received sentences ranging from deportation to 42 years in prison.

[9] According to journalist and historian Carey McWilliams, there were 531 indictments for violation of the Criminal Syndicalism Act between 1919 and 1924, and "Of those arrested, 264 were tried, 164 convicted, and 128 were sentenced to San Quentin Prison for terms of from one to fourteen years.