Social Christian Unity Party

The Social Christian Unity Party (Spanish: Partido Unidad Social Cristiana, PUSC) is a Costa Rican centre-right political party. Founded in 1983, it traces its ideological origins to Calderonism, the political movement associated with the reforms of President Rafael Ángel Calderón Guardia and the National Republican Party, which governed from 1940 to 1948.

The PUSC was established through the merger of the 4 parties that had previously formed the Unity Coalition: the Christian Democratic Party, the Republican Calderonista Party, the People's Union Party, and the Democratic Renovation Party. It is a member of the Christian Democrat Organization of America (ODCA) and advocates a political platform based on Christian-democratic principles, including social solidarity, representative democracy, and a market economy tempered by social responsibility.

From its foundation until the early 2000s, the PUSC was one of Costa Rica's two dominant political parties, alongside the National Liberation Party (PLN), forming the core of the country's two-party system. During this period, the party won three presidential elections and provided three presidents: Rafael Ángel Calderón Fournier (1990–1994), Miguel Ángel Rodríguez Echeverría (1998–2002), and Abel Pacheco de la Espriella (2002–2006).

Although its electoral influence has declined since the mid 2000s amid a series of corruption scandals involving former party leaders, the PUSC has remained one of Costa Rica's principal political parties and continues to hold representation in the Legislative Assembly.

In Costa Rican political discourse, the party is commonly referred to simply as La Unidad ("The Unity"), while its supporters are known as socialcristianos ("social Christians") or, colloquially, as mariachis.

History

Efforts to unite Costa Rica's principal opposition parties into a permanent political force capable of challenging the dominance of the National Liberation Party (PLN) began in the early 1970s. In 1977, four parties—the People's Union Party, the Christian Democratic Party, the Republican Calderonista Party, and the Democratic Renovation Party—formed the Unity Coalition (Coalición Unidad).