Socialist Challenge was a Trotskyist group in English Canada formed by former members of the Revolutionary Workers League/Ligue Ouvrière Révolutionnaire who were expelled or resigned when the RWL moved away from Trotskyism in the early 1980s.
In 1977, supporters of the Revolutionary Marxist Group and a separate Quebec organization, the Groupe Marxiste Revolutionnaire, united with the League for Socialist Action and the Ligue Socialiste Ouvrière to form the Revolutionary Workers League/Ligue Ouvrière Révolutionnaire which became the new Canadian section of the reunified Fourth International.
[1][2] Socialist Challenge underwent a severe split in 1994 when Barry Weisleder, the editor of the newspaper, was expelled.
In 1999, Socialist Challenge formally dissolved as an independent group and became the Fourth International Caucus of the NSG.
[3] Gauche Socialiste still exists as an autonomous section of the Fourth International, and maintained "fraternal relations" with the NSG.