Regional Rebellion
From 1957 to 1961, Tan Goan-Po supported the regional, but not separatist, PRRI/Permesta rebellion based in central Sumatra and north Sulawesi, the area where he was born. These regions, as well as other islands outside of Java, suffered from the nation's centralized economic policies, under which most of the wealth and resources produced outside of Java were directed to the development of Java, leaving the "Outer Islands" economically neglected. Simultaneously, constitutional democracy was declining and degenerating into Sukarno's "Guided democracy".
Tan was an economic advisor in the rebellion effort, and lived in exile for about four years. He and his family lived in the Netherlands, Switzerland, Singapore, Hong Kong, and Malaysia, moving from one country to the next when a visa expired or when asked to leave by the host country. During the banishment period, he was in the company of other exiled families, such as the families of Sumitro Djojohadikusumo, Alex Kawilarang, Joop Warouw, Des Alwi, and Petit Muharto Kartodirdjo.
In 1961, the rebellion was defeated and the government offered amnesty to those who surrendered. On 2 October 1961, Tan surrendered at the Indonesian Embassy in Kuala Lumpur, Malaysia, and was quarantined in a political detention center in Cipayung, West Java, for reindoctrination lasting approximately 2 months. He was detained along with other rebels such as Ventje Sumual, a commander of the PRRI ground forces, and Ir. Herling Laoh, who was twice a cabinet member. During the detention, some attempts were made to indoctrinate the detainees in Sukarno's economic and political policies.
As part of a condition for his amnesty, Tan was barred from ever participating in politics or holding a position in any public or government institution. Therefore, a job at a public university, such as Universitas Indonesia, whose economics department he helped found, was now closed to him.