In 1987 General Augusto Pinochet, the de-facto President of Chile, legalized the political parties and called a plebiscite to determine whether or not he would remain in power. Several parties, including the Christian Democracy, the Socialist Party and the Radical Party, gathered in the Alianza Democrática (Democratic Alliance). In 1988, several more parties, including the Humanist Party, the Ecologist Party, the Social Democrats, and several Socialist Party splinter groups added their support, despite fears of election fraud by Pinochet, and the "Concertación de Partidos por el NO" ("Coalition of Parties for NO") was formed in an attempt to overthrow the General.
During the electionary period, the Coalition organized a colorful and cheerful campaign under the slogan "La alegría ya viene" ("Joy is coming"). Some Socialist factions were the last to join, because they were reluctant to work in the plebiscite, fearing an election fraud by Pinochet. On October 5, 1988, the "NO" vote won with a 54% majority, and a general election was called for 1989.
In that year, the coalition changed their name to Concertación de Partidos por la Democracia ("Concert of Parties for Democracy") and put forward Patricio Aylwin, the Christian Democrat leader, as a presidential candidate, as well as launching a common list for the parliamentary elections. In elections the following year, Aylwin won and the coalition gained the majority of votes for the parliament. However, due to the binomial system, they had no majority in parliament, a situation they found themselves in constantly for over 15 years. This forced them to negotiate all law projects with the right-wing parties, the Unión Demócrata Independiente (UDI) and Renovación Nacional (RN) (later coalesced into the Alliance for Chile).
In 1993, the coalition put forward the Christian Democrat senator Eduardo Frei Ruiz-Tagle as a presidential candidate. Frei was the son of Eduardo Frei Montalva, the founder of the Christian Democrat Party and himself a former President of Chile (1964-1970). Gaining 57% of the votes, he defeated to the right-wing candidate, Arturo Alessandri Besa, becoming the third Christian Democrat president, and the second Coalition president.
In the same year, the Humanist Party, the Christian Left, and the Greens left the Coalition, accusing it of betraying the purpose for which it was born. The Social Democrat Party and the Radical Party joined together to form the Social Democrat Radical Party, while the various former Socialist factions became part of the Socialist Party.
Frei's government faced two main problems: an economic crisis was raising the unemployment rate, and General Pinochet had been arrested in London. Both situations led the Coalition to fear defeat in the 1999 presidential elections.
In that year, the coalition had two possible candidates: the Christian Democrats' Andrés Zaldívar and the Socialists' Ricardo Lagos. Primary elections were held to decide between the two. Lagos won the vote, and went on to defeat the UDI's Joaquín Lavín in the presidential election. However, since he got a plurality as opposed to a majority of the votes, a runoff vote was held, the first in Chilean history, in which Lagos won with 51% of the votes.
In 2005, two candidates were again proposed: the Christian Democrats' Soledad Alvear, a former Minister of Foreign Affairs, and the Socialists' Michelle Bachelet, a former Minister of Defense. As before, the situation was to be resolved through a primary election. However, in May 2005, after months of internal disputes regarding her party's directives, Alvear withdrew from the presidential race, deciding instead to run for senator in Santiago. Bachelet therefore became the Coalition's candidate, and the second woman to run for Chilean President (the first being Communist leader Gladys Marín), competing with the IDU's Joaquín Lavín and NR's Sebastián Piñera.
On December 11 2005, Bachelet won with 45% of the votes, but was forced to compete with Piñera in a runoff election. In the same month, the coalition won 51.25% of the votes in the parliamentary elections, gaining 20 seats in the Senate and 65 seats in the Chamber of Deputies. This gave them, for the first time, the majority in both Houses, even with the binomial system working.
On January 15, 2006, the runoff was held. Bachelet won with nearly the 54% of the votes, becoming the first female president of Chile. She was also the fourth Coalition candidate and third Socialist to win.