The Indonesian Democratic Party (PDI) was created from a fusion of the three secular parties: the Indonesian Nationalist Party (PNI), the League of the Supporters of Indonesian Independence (IPKI), and the Party of the Masses (Partai Murba)and two Christian parties: the Indonesian Christian Party (Partindo) and the Catholic Party (Partai Katolik).

The PNI, the largest of the PDI's five parties, and the legatee of Sukarno, had its base in East and Central Java. IPKI had been strongly anti-PKI in the Old Order in contrast to the once-leftist Partai Murba. Even more heterogeneous than the PPP, the PDI, with no common ideological link other than the commitment to the Pancasila as its sole principle, was faction-ridden and riven with personality disputes, held together only by direct government intervention into its internal affairs. It was only under the auspices of the minister of home affairs that the PDI Executive Committee could meet at all after the 1983 elections.

The government insisted on keeping the PDI viable to avoid the risk of polarization and a direct Golkar-PPP, secular-Islamic face-off. With the gradual public rehabilitation of the late President Sukarno as an "Independence Proclamation Hero" and the father of the Pancasila, the PDI was not reluctant to trade upon the Sukarnoist heritage of its component party, the PNI.