Tang was elected to the National Assembly in 1996. He won a seat on the Legislative Yuan in 2001 and 2004, losing his bid for a third term in office in 2008.[3] He faced Lee Wen-chung in a Democratic Progressive Party primary for the Nantou County Magistracy in 2013, and lost.[4][5] Tang contested a 2015 legislative by-election in Nantou, but lost to Kuomintang candidate Hsu Shu-hua.[6] Later, Tang became the assistant director of the Executive Yuan's Central Taiwan Joint Services Center.[7]
Tang opposed exorbitant penalties against individuals who illegally raise endangered animals, believing that if the private efforts prove more successful than government-supported attempts, the government should respond in a pragmatic manner to promote better methods of conservation.[8] He has criticized the Executive Yuan for funding civic groups that enable former government officials to collect an income in addition to their pensions.[9] During his legislative tenure, Tang has repeatedly drawn attention to the increasing personnel costs of the Republic of China Armed Forces,[10][11] maintaining that he favors military spending to be focused on weaponry and research instead.[10] As a legislator, Tang participated in many discussions about the state of Taiwan's military.[12][13][14][15] He has frequently proposed that the government purchase military equipment from other nations.[16][17][18] Tang has also pushed the government to review immigration policy and foreign spouses who use Taiwanese partners to obtain Republic of China citizenship for themselves and family outside of Taiwan.[19]