<Li> World Socialist Party of the United States </Li> <Tr> <Td> Defunct parties (show) <Ul> <Li> American Labor Party </Li> <Li> American Workers Party </Li> <Li> Black Panther Party </Li> <Li> Communist League of America </Li> <Li> Communist Workers' Party </Li> <Li> Democratic Socialist Federation </Li> <Li> Democratic Socialist Organizing Committee </Li> <Li> Farmer--Labor Party </Li> <Li> Maoist Internationalist Movement </Li> <Li> New American Movement </Li> <Li> Proletarian Party of America </Li> <Li> Puerto Rican Socialist Party </Li> <Li> Social Democracy of America </Li> <Li> Social Democratic Federation </Li> <Li> Social Democratic Party of America </Li> <Li> Social Democrats, USA </Li> <Li> Socialist Labor Party of America </Li> <Li> Socialist Party of America </Li> <Li> Students for a Democratic Society </Li> <Li> Weather Underground </Li> <Li> White Panther Party </Li> <Li> Workers Party of the United States </Li> <Li> Youth International Party </Li> </Ul> </Td> </Tr> <Ul> <Li> American Labor Party </Li> <Li> American Workers Party </Li> <Li> Black Panther Party </Li> <Li> Communist League of America </Li> <Li> Communist Workers' Party </Li> <Li> Democratic Socialist Federation </Li> <Li> Democratic Socialist Organizing Committee </Li> <Li> Farmer--Labor Party </Li> <Li> Maoist Internationalist Movement </Li> <Li> New American Movement </Li> <Li> Proletarian Party of America </Li> <Li> Puerto Rican Socialist Party </Li> <Li> Social Democracy of America </Li> <Li> Social Democratic Federation </Li> <Li> Social Democratic Party of America </Li> <Li> Social Democrats, USA </Li> <Li> Socialist Labor Party of America </Li> <Li> Socialist Party of America </Li> <Li> Students for a Democratic Society </Li> <Li> Weather Underground </Li> <Li> White Panther Party </Li> <Li> Workers Party of the United States </Li> <Li> Youth International Party </Li> </Ul> <Li> American Labor Party </Li>

Unionization efforts in the period from 1900 to 1920