During the Indonesian National Revolution, Tahija was the adjutant of Simon Spoor. Despite his position, he maintained good personal relationships with nationalist leaders, especially Sutan Sjahrir. Between 1946 and 1949, he also played a part in the formation of the State of East Indonesia (NIT). He was one of the candidates for the state's first provisional legislature, though he was defeated in the leadership vote by Tadjoeddin Noor. He also served in the Cabinet of the State of East Indonesia, where he initially was made Minister of Social Affairs under Nadjamuddin Daeng Malewa's first cabinet, and later taking up the post of Minister of Information in Malewa's second cabinet between 2 June and 11 October 1947. His next cabinet post was the Minister of Economy between 11 October and 15 December 1947 in S.J. Warrouw's cabinet. He then became head of NIT's representative office in Jakarta. Journalist Rosihan Anwar wrote that Tahija approved of the 1947 Dutch offensive against the Indonesian nationalist forces, but disapproved of the second, 1948 offensive.