The Working Committee of the KNIP became part of the People's Representative Council when Indonesia became a unitary state in 1950.

[3] In March 1945, the Japanese established the Investigating Committee for Preparatory Work for Independence (Indonesian: Badan Penyelidik Usaha Persiapan Kemerdekaan) or BPUPK, chaired by Radjiman Wediodiningrat, with Sukarno, Hatta and Thamrin among its members.

[4][5] On 7 August, the day after the atomic bombing of Hiroshima, the Preparatory Committee for Indonesian Independence (PPKI) was established.

The upper chamber, the People's Consultative Assembly would then have six months to draw up a new constitution, leaving open the possibility that this would be an entirely new document free of the influence of the situation prevailing during the Second World War.

[9][10] Following pressure by individuals including Sutan Sjahrir and Amir Sjarifuddin for a less authoritarian system of government, on 16 October 1945, Vice-president Hatta issued Vice-Presidential Edict No.X transferring the powers the Constitution conferred on the People's Consultative Assembly and People's Representative Council from the president to the KNIP, making the government more parliamentary in nature.

At the end of 1946, there was "manipulation" of the KNIP membership when it appeared likely the body would reject the Linggadjati Agreement between the Dutch and the Indonesian republicans.

The number of left-wing members increased sharply as they wanted the Dutch military action to be ended as quickly as possible.

The proportion of seats held by the Left Wing increased dramatically following President Sukarno's appointments.