Social Christian Unity Party

In 2004-2005 a series of corruption scandals involved three former presidents of Costa Rica; Rafael Ángel Calderón Fournier, Miguel Ángel Rodríguez Echeverría and José María Figueres Olsen.[4] All of them suspects of bribery and enticement. They were accused of receiving money in exchange for guaranteeing very profitable contracts between private companies Alcatel and Fischel with State's corporations.[5] The scandals even caused Calderón and Rodríguez to be arrested, prosecuted and in Calderón's case condemned,[6] while Figueres wasn’t arrested as he was in a non-extraditable country. Rodríguez was acquitted on a technicality.[7][8]

The party's candidate in 2006 right after the scandals was Pacheco's Prime Minister Ricardo Toledo. Toledo received only 3% of the votes, an unthinkable result for what was once one of Costa Rica's main parties. Anti-corruption party Citizens Action saw an increase in its support receiving almost as many votes as PLN and replacing PUSC as PLN's main rival. PUSC also passed from 17 to 5 seats after the 2006 parliamentary election and from 58 to 9 mayors in that year's municipal election.

In 2010 the party's nominee was former Vice President Luis Fishman. Fishman was the first Jewish presidential candidate in Costa Rica's history and gained 5% of the votes keeping the 5 seats.[2] In 2013 Calderón suggested Dr. Rodolfo Hernández, then director of Costa Rica's Children's Hospital, as 2014's presidential nominee. Hernández faces former minister in Miguel Ángel Rodríguez’ cabinet Rodolfo Piza in the 2013 party primary showing, again, the traditional fight between the Calderonist and Liberal factions (the liberals having control over the National Committee). Also, as usual for a victorious candidate in PUSC's primaries, Hernández won with 75% of the votes.

Hernández received very good support and for a while was the second most popular candidate after PLN's Johnny Araya. Yet Hernández resigns as candidate on October 3, 2013 alleging constant backstabbing and treacheries from PUSC's authorities, so the party's nomination was taken by Rodolfo Piza.[9][10] Piza obtained only 6% of the vote (as slight improvement) and was the fifth candidate in popular vote, but most notable was PUSC's increase in the parliamentary vote becoming the fourth most voted party surpassing Libertarian Movement (till then normally the third-largest party since 2006) and increasing its legislative caucus from six to eight seats.[11]

In 2015 Calderón and his followers left the party and founded a new one called Social Christian Republican Party (an allusion to Calderón's father historical party). Nevertheless, PUSC saw a victory in the 2016 municipal election gaining second place in municipal votes surpassing ruling PAC and receiving much more votes than Calderón's new party. PUSC obtained 15 mayors (second in number after PLN) and saw an increase in its electoral support, unlike PLN that although the more voted party did saw a decrease in support.[12]

In 2016, the PUSC declared themselves in favor of equal rights for same-sex couples in terms of marital property, insurance with the Costa Rican Social Security Fund (CCSS) and death inheritance, while still not supporting same-sex marriage.[13]