“The Only Tool That’s Effective” by Taisto Luoma, One Big Union Monthly February 1938.

This cartoon appeared on the cover of the IWW publication, The One Big Union Monthly and portrays the IWW using the tool of the general strike to dethrone capitalism and claim the factories for the workers while the socialists and communists look on from the sidelines in shock and amazement.

See this image in the Solidarity Forever: A Look at Wobbly Culture exhibit.