苗栗縣第1選區國民黨立委李乙廷因賄選官司,遭法院判決當選無效定讞,成爲台灣史上因當選無效喪失立委資格,而必須補選的首例。補選結果,國民黨提名李乙廷的妻子陳鑾英,卻敗給退出國民黨參選的竹南鎮長康世儒,在台灣政壇引發廣泛的討論。本文以責任政治的角度出發,利用民意調查的個體資料,探討導致國民黨票源流失以致敗選的因素。尤其聚焦於選民對李乙廷賄選官司判決的觀感,在其投票抉擇中所扮演的關鍵影響力。研究發現,除了康世儒以現任竹南鎮長的優勢,並在民進黨放棄提名的策略性支持下,有效鞏固與拓展票源外,選民對李乙廷賄選官司判決的觀感,也讓原先支持李乙廷的選民,在此次補選中採取消極不去投票,甚至轉而投給康世儒的決定,導致國民黨因選票流失而敗選。這結果也傳遞一個清楚的訊息給所有政黨及政治人物:若一旦涉案,選民將會追究其政治責任。
Former Kuomintang (KMT) legislator Yi-ting Lee's qualification was abolished by a civil trail because he was discovered to have bought votes during the 2008 legislative election. The legislative by-election was held on 14 March 2009. The KMT nominated Lee's spouse Luan-yin Chen to run against the mayor of Chunan Town, Shi-ru Kang, who left the KMT and ran the by-election as an independent candidate. Thanks to the support from Chunan Town, Kang narrowly defeated Chen. From the perspective of political responsibility, we study this by-election and explain why the KMT lost, especially if Lee's vote-buying trial influences voter choice. It is found that Kang won the by-election not only because of his Chunan Town mayor advantage and his characteristics, but also because Lee's supporters who considered Lee's trial fair may not have turned out to vote for Chen. Our analysis of this by-election, the first one since Taiwan adopted the new mixed-member majoritarian system, implies that parties and politicians who involve in a scandal may face electoral punishment.