立法院選舉採聯立制之可行性評估

Abstract

2005年修憲後，從第七屆立委選舉開始，我國採取單一選區兩票制並立制（mixed member majoritarian system, MMM）的混合式選制，到2016年為止，歷經三次選舉洗禮，但並立制代表性不足的問題，一直受到各界批評。2014年蔡英文當選民進黨主席主改為聯立制（mixed member proportional system, MMP），相較於國民黨始終堅持並立制的主張，民進黨對於選制則無一貫理念，從1998年偏好聯立制 ，2001年轉移到並立制，2014又轉向聯立制。蔡英文是否會貫徹其主張，運用國會人數優勢修憲達成選制改革的憲政主張，成為本文的研究動機。 本文以深度訪談法，訪談蔡英文幕僚、立法院資深立委以及學者專家，再以2008年、2012年及2016年立法委員選舉的結果模擬採取聯立制後，各黨立委席次的改變，結果顯示，2008年和2012均出現超額議席（overhang seats），顯見我國仍無法避免超額議席的情況，若採取聯立制將面臨違憲爭議。而立法院選舉制度如果採行聯立制，國會政黨體系將像德國一樣，難有單一政黨掌握過半席次，總統與國會間容易形成分立政府的格局。國會選制採聯立制搭配上政黨體系數多黨制，在總統國會制的憲政體制下，易形成分立政府與少數內閣。相反地，立法院選舉制度採行並立制，國會中的政黨體系通常會形成兩黨制或以兩大黨為主的政黨體系，在國會中通常會有單一政黨掌握過半數的席次，形成一致政府，憲政運作將比分立政府且少數內閣情況更為順暢。整體而言，除了超額議席難解之外，聯立制也不宜搭配我國半總統制（Semi-presidentialism）的憲政體制。

Taiwan has adopted a Mixed Member Majoritarian (MMM) System in 2005 following a constitutional reform. Since then until 2016, the MMM system, a Mixed or Hybrid System, has been tested during three major elections. However, the MMM system has long being criticized by many as it is unable to ensure fair representation of each vote. Since her winning Democratic Progressive Party (DPP) chairmanship in 2014, Tsai Ing-wen has proposed replacing the MMM system with Mixed-Member Proportional representation (MMP), saying that the system would ensure that the number of seats a party receives better mirrors the proportion of votes it received. Comparing with the Kuomintang (KMT) that has long upheld its support to MMM system, DPP, however, does not have a consistence stance on the issue. It had previously support MMP in 1998, until later turned to MMM in 2001 before finally shifting to MMM again in 2014. It remains to be seen if Tsai will push through the voting system change into MMP system during her tenure as president with the DPP majority in the Legislative Yuan. The above is the main reason and backstory behind this paper. The paper conducts in-depth interviews with Tsai’s aides, senior legisators, experts and scholars in the field, to talk about their views on the system. It also studies three Legislative elections in 2008, 2012 and 2016, and simulates how an election system change into MMP would affect elections results and political landscape. The simulation ultimately reveals overhang seats issue in both 2008 and 2012 elections. This shows the fact that it would be difficult for Taiwan to avoid overhang seats issue. Also, it would be unconditional if Taiwan changes into MMP system. Meanwhile, if Taiwan, like Germany, adopts MMP system, there will no one party enjoying majority in the Legislative Yuan. Lack of a majority in the parliament, it would turn into a divided government in Taiwan’s president parliamentarism system. MMM system, on the other hand, normally leads to two major parties in the parliament when one of them enjoys majority. This will form a united government and could make it easier for the Cabinet and the ruling administration to run, comparing with a divided government. To sum up, the paper shows that MMP system would lead to overhang seats issue and is not suitable for Taiwan’s political scene that adopts a semi-presidentialism system.