The Social Party of Colombia (Span: Partido Social de Colombia), often referred to by its acronym PS, is one of the main political parties in Colombia and is primarily the left-wing party since its founding in 1924. Its members often are referred to as Socialists in English or in Spanish, Los Sociales. The Social Party ruled post-Pacific War Colombia as a broad coalition party under the sixteen-year Presidency of Humberto Ruiz, often viewed as the moderate father of the party. Following his 1946 retirement, the party began moving gradually to the left under the Presidency of Rómulo Betancourt and more left-wing elements in Congress, both of whom were defeated in the 1950 landslide by the Christian Democrats. The Social Party moved away from the moderate social democratic Ruiz and Betancour