"Prejudices of Race and Nationality Benefit Only the Master Class" by Maurice Becker, Industrial Pioneer July 1921.

While most labor unions excluded workers from membership on the basis of race or ethnicity, the IWW preached a message of inclusive unionism. Here Wobbly cartoonist, Maurice Becker, warns workers of the inherent dangers of allowing themselves to be deluded with notions of racial supremacy. Through this work Becker conveys the message that all workers, regardless of color or ethnicity, are members of the same class and racial divisions can only dilute the strength of the labor movement.

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