The Workers' Socialist Movement (Spanish: Movimiento Socialista de los Trabajadores, abbreviated MST), known for many years as the Workers' Socialist Party (Partido Socialista de los Trabajadores, abbreviated PST), is a Trotskyist political party in Bolivia.
[1][2][3] PST emerged from a Morenoist fraction of the Socialist Party-1 of Marcelo Quiroga Santa Cruz in the late 1970s.
The PST was established, and legally recognized, as the Workers' Socialist Organization (Organización Socialista de los Trabajadores, OST) in 1980.
[5][6][7] In 1984 the PST had several delegates present at the sixth congress of Central Obrera Boliviana (COB), including factory workers from La Paz and teachers from Oruro.
[10] Whilst Solón (later the Ambassador of Bolivia to the United Nations) is no longer affiliated with the organization, Jaime Vilela Gutiérrez remains in the leadership of MST.