Yes, the letter exists. Jack London's resignation letter from the Socialist Party is displayed in the museum on his estate. As Wikipedia states, the 1916 letter stated his disgust at the party's "lack of fire and fight", and its loss of emphasis on the class struggle. Not mentioned by Wikipedia is that Mr. London's letter closed by stating (paraphrase) that the prize jewels of justice, liberty, and self-determination cannot be simply handed over to all the lesser classes and races. They must be earned, and if they do not earn them, they will forever remain what they are; inferior classes and races. He signed it "Yours for the Revolution, Jack London".
Freedom Socialist Party was created in 1966.
Socialist Party of Vietnam ended in 1988.
There’s more than one answer. The Socialist Party of America was one.
the socialist party
The Socialist Labor Party was founded in 1891
Socialist Party of Massachusetts was created in 197#.
Socialist Party of Yugoslavia was created in 1921.
Socialist Party of Albania was created in 1991.
Portuguese Socialist Party was created in 1875.
Portuguese Socialist Party ended in 1933.
Socialist Party of Slovenia was created in 1990.
Socialist Party of Slovenia ended in 1994.