 Rafael Paasio of the SDP subsequently became Prime Minister and formed a popular front government consisting of the SDP, the Centre Party, the People's Democratic League (SKDL), and the Social Democratic Union of Workers and Smallholders (TPSL) in May 1966.Prior to the elections, Centre Party Prime Minister Johannes Virolainen had led a centre-right coalition government since September 1964.Meanwhile, Paasio had moved the SDP further to the left in order to attract back voters from the TPSL.