The Communist Party of Slovakia (, KSS) was a Marxist-Leninist party in the Slovak Socialist Republic. It was formed in May 1939, when the Slovak State was created, as the Slovak branches of the Communist Party of Czechoslovakia (KSČ) were separated from the mother party. When Czechoslovakia was again established as a unified state, the KSS was still a separate party for a while (1945–1948). On 29 September 1948, it was reunited with the KSČ and continued to exist as an "organizational territorial unit of the KSČ on the territory of Slovakia". Its main organ (and thus the main newspaper in Slovakia at the time) was Pravda.

After the merger KSS functioned as a regional affiliate of the KSČ, not as an independent political institution. Therefore, the organizational structure of the KSS mirrored that of the KSČ: the KSS Congress held session for several days every five years (and just before the KSČ's Congress), selecting its Central Committee members and candidate members, who in turn selected a Presidium, a Secretariat, and a First Secretary (i.e. party leader).

The most important first secretaries were Alexander Dubček (1963–1968) and Jozef Lenárt (1970–1988). Following the March 1986 party congress, the KSS Presidium consisted of 11 members; the Secretariat included, in addition to Lenárt, three secretaries and two members; and the Central Committee comprised 95 full members and 36 candidate members. The KSS in 1986 also had its own Central Control and Auditing Commission, four other commissions, twelve party departments, and one training facility.

KSS ceased to exist in 1990 (following the Velvet Revolution), when it was transformed into the independent social democratic party called the Party of Democratic Left (SDĽ). Most of that party, in turn, is now part of Direction – Social Democracy, which had separated from the SDĽ in 2000.

A new Communist Party of Slovakia was, however, founded in 1992 from a merger of the Communist Party of Slovakia – 91 and Communist League of Slovakia.

Leaders Party leaders (1944–1990) 1944–1945: Karol Šmidke 1945–1951: Štefan Bašťovanský 1951–1953: Viliam Široký 1953–1963: Karol Bacílek 1963–1968: Alexander Dubček 1968: Vasiľ Biľak 1968–1969: Gustáv Husák 1969–1970: Štefan Sádovský 1970–1988: Jozef Lenárt 1988–1990: Ignác Janák

Chairman of the Board of Commissioners for Slovakia (1945–1960) 1945–1946: Karol Bacílek 1946–1950: Gustáv Husák 1950–1951: Karol Bacílek 1951–1953: Július Ďuriš 1953–1960: Rudolf Strechaj

Prime Ministers of the Slovak Socialist Republic (1969–1990) 1969: Štefan Sádovský 1969–1988: Peter Colotka 1988–1989: Ivan Knotek 1989: Pavol Hrivnák 1989–1990: Milan Čič

Election results Slovak assembly elections

Date Leader Votes Seats Position # % # ± Size 1946 Karol Šmidke 489,596 30.61 31 2nd Coalition 1948 Štefan Bašťovanský 47 1st Majority 1954 Karol Bacílek 28 1st Majority 1960 Karol Bacílek 2 1st Majority 1964 Alexander Dubček 13 1st Majority 1971 Jozef Lenárt 44 1st Majority 1976 Jozef Lenárt 1 1st Majority 1981 Jozef Lenárt 1 1st Majority 1986 Jozef Lenárt 1 1st Majority 1990 Peter Weiss 450,855 13.35 81 4th Opposition

See also Communist Party of Bohemia and Moravia Communist Party of Slovakia – 91 Communist Party of Slovakia Slovak Socialist Republic Central National Revolutionary Committee

References