Its members were Senators Raúl Ampuero and Tomás Chadwick Valdés with Deputies Ramón Silva Ulloa, Eduardo Osorio Pardo, Óscar Naranjo, Andrés Aravena and Ernesto Guajardo.

Once elected Tarapaca did not assume government positions, but participated in social fronts.

Following the coup d'état of September 11, 1973 decided to dissolve in exile.

It was rebuilt in 1983, with Silva Ulloa as Secretary General, participating in the Democratic Alliance and later becoming one of the founders of Concertación.

Between 22 and 25 January 1990 it participated in the Congress of Unity Salvador Allende, returning to the Socialist Party.