The Socialist Party-One took part in the 1978, 1979, and 1980 general elections, running Marcelo Quiroga Santa Cruz and polled 00.43, 04.82 and 08.71 per cent of the vote, respectively.
[1] Some elements in the conservative military feared Marcelo Quiroga Santa Cruz's potential following as an opposition leader and he was killed during the Luis García Meza Tejada coup of 17 July 1980.
[2] In 1984 the Socialist Party-One absorbed the small ultra-left “Spartacus Revolutionary Movement” (Movimiento Revolucionario Espartaco, MRE), led by Dulfredo Rua.
[3] The Socialist Party-One presented Ramiro Velasco Romero as its candidate in the 1985 elections, but he won only 02.58 per cent of the vote, coming sixth.
[5] In 1993 the Socialist Party-One took part in an electoral coalition United Left backing Ramiro Velasco Romero, a leader of the PS-1.