The Union of Democratic Forces (, СДС / SDS) is a political party in Bulgaria, founded in 1989 as a union of several political organizations in opposition to the communist government. The Union was transformed into a single unified party with the same name. The SDS is a member of the European People's Party (EPP). In the 1990s the party had the largest membership in the country, with one million members, but has since splintered into a number of small parties totaling no more than 40,000 members. The SDS proper had 12,000 members in 2016. History Dissident groups formed under the faltering regime of Todor Zhivkov in the late 1980s were the basis for the Union. Once Zhivkov fell, a loose political confederation was envisioned where constituent groups could continue to work for their own cause, while the coordinating council would include three members from each organization. The Longtime dissident philosopher Zhelyu Zhelev, who would later become Bulgaria's president, was elected chairman, and Petar Beron, a well-known environmental scientist, was chosen as secretary. The SDS was officially founded on 7 December 1989 as a union of eleven political organizations, such as Ekoglasnost, Bulgarian Social Democratic Workers' Party (United) and Bulgarian Agrarian People's Union "Nikola Petkov". The following year, six more parties were incorporated (Radical Democratic Party, Green Party of Bulgaria, Democratic Party, New Social Democratic Party, United Democratic Centre, Democratic Front). The SDS lost the 1990 elections to the Bulgarian Socialist Party but still participated in the joint cabinet of Dimitar Iliev Popov. On 15 May 1991 39 members left the SDS because of disagreements with the draft of the new constitution and founded the new organizations SDS-Center and SDS-Liberals. Later the remnants of the SDS formed their own cabinet with Prime Minister Filip Dimitrov in November 1991, though the cabinet lasted only a little over a year when the government failed a motion of confidence in September 1992. The socialists, together with the Movement for Rights and Freedoms, formed a coalition government headed by Prof. Lyuben Berov. Following the resignation of Berov's cabinet in October 1994, the BSP went on to win the 1994 elections. However, following discontent over economic problems, Prime Minister Zhan Videnov resigned at the end of 1996, clearing the way for new elections, this time won by the SDS with a crushing 55% vote. Party leader Ivan Kostov went on to form the new government