Independent Socialist League

The Independent Socialist League was the group created when the Workers Party dissolved itself as a party and reorganized as a propaganda group in 1949. They had reorganized as a propaganda group because their perception of the possibility of forming a revolutionary political party in the US had by diminished by 1949. The Independent Socialist League (ISL) continued to publish Labor Action.

The Young People's Socialist League (YPSL) left the Socialist Party of America in 1953 and joined with the ISL-affiliated Socialist Youth League to form the Young Socialist League (YSL).

The left wing of the Young Socialist League were meeting with members of the Socialist Workers Party from early 1957 on. In the summer of 1957 the ISL voted to enter the Socialist Party/Social Democratic Federation (SP/SDF). The left YSLers were expelled in late 1957. In 1958 ISL members entered the SP/SDF and the ISL dissolved.