Chien was elected to two terms as a member of the Legislative Yuan and served from 1996 to 2002.[3] A legislative representative of the Democratic Progressive Party, Chien belonged to its New Tide faction.[3][4] In 1999, he worked to pass stronger legislation protecting conscientious objection to military service on religious grounds after the Judicial Yuan ruled that such reasoning was not sufficient to refuse conscription.[5] Chen spoke out against black gold politics later that year, citing data collected by the National Police Agency.[6] In 2000, Chien was attacked by Lo Fu-chu and Lin Ming-yi.[7] Lo later gained a reputation for using violence on the legislative floor.[8]
After stepping down from the legislature in 2002, Chien became leader of the Peacetime Foundation.[9] Through the foundation, Chien advocates peace on both sides of the Taiwan Strait, leading to a formally independent Taiwan,[10][11] negotiation with Chinese civic groups on Cross-Strait issues,[12] and organizes the Peace Film Festival.[13] Chien founded the Alliance of Fairness and Justice, also known as the Pan-Purple Coalition, on 10 August 2003 and announced that he would represent the coalition of social groups as its presidential candidate in the 2004 elections, but soon left the race.[3][14] Since leaving office, Chien has supported many social causes and initiatives. Among them are judicial reform and tax reform,[15][16] as well as workers' rights.[17] Chien has also called for the government to fund programs that would raise Taiwan's birth rate.[18][19] In 2005, he pushed the Chen Shui-bian administration to adopt less demeaning Chinese translations of the words "Jew" and "Islam".[20] The next year, Chien helped lead the Million Voices Against Corruption, President Chen Must Go campaign alongside Shih Ming-teh.[21][22]
Chien later joined the Alliance for Fair Tax Reform to serve as its spokesman,[23][24] leaving the group to establish the Anti-Poverty Alliance.[25] Led by Chien, members of the Anti-Poverty Alliance held two hunger strikes in October 2011 to raise awareness of economic inequality in Taiwan.[26] In 2012, Chien, representing the Anti-Poverty Alliance, was named to the Executive Yuan Tax Reform Committee alongside Wang Jung-chang of the Alliance for Fair Tax Reform. Chien and Wang had previously worked together prior to this as members of the Pan-Purple Collation. Additionally, both were members of an earlier convocation of the Tax Reform Committee which met from June 2008 to December 2009.[27] Chien published a book, Power of the Weak in 2015. In it he advocated for the government to adopt nonviolent civil resistance as part of a strategy for national defense.[28] Chien's Anti-Poverty Alliance supported third force political candidates in the 2016 elections, the most successful of which belonged to the New Power Party.[29]
