Taruc was elected to the Philippine House of Representatives in 1946 as a member of the Democratic Alliance (the party led by Sergio Osmena). He and five other elected Democratic Alliance candidates opposed the constitutional amendment that would give American businessmen parity rights with Filipinos in exchange for US rehabilitation funding. In particular, Luis opposed the Bell Trade Act, the Parity Amendment to the Constitution, and the Military Bases Agreement. To secure the majority necessarily to pass the amendment President Manuel Roxas arranged for Taruc and the other oppositional Democratic Alliance members ejected from office by the Commission on Elections on the grounds that they had been committing election fraud and terrorism.