ASSOSS was originally a left liberal organization founded in 1912 which moved leftward in the sixties.
After the split of the trotskyist Ligue Communiste Révolutionnaire (LCR) in 1970 the majority of GSR was renamed in KBL in 1972.
In 1979 KBL was the driving force behind the electoral Alternativ Lëscht – Wiert Iech which won 0,7 p.c.
In the same year the majority of KBL left and founded the short-lived organization Fir de Sozialismus.
[2] Other leading members were Jean Heisbourg, Robert Medernach, Lucien Blau, Thers Bodé.