[1] It was formed in 2014 by the former League of Workers for Socialism – Countercurrent (Liga de Trabajadores por el Socialismo – Contracorriente, LTS-CC) for registration with the National Electoral Institute.

The expelled group formed the "Trotskyist Revolutionary Fraction", then adopting the name League of Workers for Socialism (LTS).

The LTS had acriticisms of the EZLN's strategy during negotiations with the government, saying that the peace talks and the San Andrés Pact signed between the PRI and the EZLN in 1995 were a departure from the worker and peasant unrest and prevented the spread of struggle for land and the unity of the demands of all the people in one revolutionary movement against the government.

They called for the left and the Mexican workers and peasants to maintain an independent struggle against the NAFTA and the revolutionary overthrow of the government.

[2] Since 2004 they impart the Free Cathedra Karl Marx with agendas seeking to recover and interpret current events from Marxism in university classrooms.

[7] In 2016, after the Political Reform of the Federal District, the MTS decided to participate in the election of the Constituent Assembly of Mexico City with an independent candidacy.