Madiun Uprising

The Madiun Affair or Peristiwa Madiun was an armed conflict between the government of the Republic of Indonesia and the left-wing opposition group, Front Demokrasi Rakyat (FDR, People's Democratic Front) during the Indonesian National Revolution. The conflict began on 18 September 1948 in Madiun, East Java, and ended three months later when most FDR leaders and members were detained and executed by the Indonesian authorities.

Opinions regarding the trigger of the conflict vary. According to Kreutzer, the downfall of Amir Sjarifuddin government in January 1948 was the origin of the Madiun Affair. Before then, during the second half of the 1947, Partai Sosialis was split into two factions; one faction was led by Sjarifuddin and the smaller faction led by Sutan Sjahrir. Sjahrir group's opposition grew bigger as Sjarifudin put strong emphasis on their alignment with Russia and class welfare. Sjahrir believed that Marxist doctrine of class welfare could not be applied in Indonesian community as there were no such Indonesian bourgeoisie, and that Indonesia should maintain a "positive neutrality," so that Indonesia could contribute to world peace. They completely split soon after the establishment of Hatta's presidential cabinet.

Sjarifuddin premiership ended on 28 January 1948. Prior to this, Sjahrir, Dr. Leimena, and several political activists approached Hatta and requested him to become the next prime minister. Hatta agreed on the condition that he got PNI and Masjumi's support. Driven by the need to form a cabinet with national support (both right-wing and left-wing), Hatta offered Sjarifuddin's faction some posts in the cabinet. They declined Hatta's offer and demanded key positions, including Sjarifuddin position as Minister of Defense (In the previous cabinet, Sjarifuddin was both Prime Minister and Minister of Defense) in return of their support for Hatta's government. Negotiation failed, and on January 31, 1948, Hatta finally formed a cabinet without the Sajap Kiri (left-wing) parties. Two members of Partai Sosialis, however, were included in the cabinet based on a strong request by Sjahrir. Sjahrir and the two cabinet members were expelled from the Partai Sosialis and formed their own party called Partai Sosialis Indonesia (PSI, the Socialist Party of Indonesia). "This new party immediately gave its support to Hatta's government." Hatta's program of government was based on two priorities; the implementation of the Renville Agreement, and the rationalization of the Indonesian army.

...
Wikipedia