|Abstract: ||在日本的政治脈絡下，連任多次的資深議員，多有著相當穩定的支持基礎，新人若是想要挑戰資深的現任者，不是很容易的事。但是， 2009年眾議院選舉，多位執政黨資深議員連任失利，輸給沒有從政經驗的新人。為了探討此一問題，本文以 2009年茨城第六選區為例，採質性研究方法，參考相關文獻與報導，並輔以訪談方式，探討在當地缺乏知名度與地緣關係的新人大泉博子，如何透過特定議題「廢除後期高齡者醫療制度」來突破劣勢，打敗資深議員丹羽雄哉贏得選舉。研究發現，因為後期高齡者醫療制度不管在名稱、制度設計以及執行上，都引發民眾的質疑與反彈，雖然該制度主要是影響年長者，跟其他年齡層較無關係，但是反對黨候選人大泉博子與支持團體茨城縣醫師會，在選舉策略上，將問題訴諸於一般民眾，而不僅只限於年長者，利用人們對於未來的不安，創造集體的焦慮，產生「改變」的需要。其次，反對黨也利用選制改革之後，政黨形象與個別候選人關連性提高的特性，將政策責任歸屬與執政黨候選人丹羽雄哉做連結，讓選民覺得，必須投票給反對黨的候選人，才有可能廢止這個不受歡迎的政策，也就是藉由形成投票的迫切感，成功地動員原來支持現任者的選民，改變投票行為轉而支持新人。|
It is always challenging for an inexperienced candidate to compete with an incumbent. By drawing upon a combination of archival research and fieldwork, this paper uses the sixth district in Ibaraki Prefecture as a case study to investigate how challengers are able to use policy issues to overcome the drawbacks of lacking name recognition and local networks, and win elections. In 2009, the challenger Hiroko Ooizumi called for abolishing the unpopular newly-implemented Health Insurance System for the Elderly which was interpreted as “bullying the senior.” This system mainly affected people aged at least 75 and was considered to be a niche issue. However, Ms. Ooizumi and her major support group, the Ibaraki Medical Association, strategically appealed to the public instead of elderly people only, by arguing that everybody could be affected sooner or later, thereby creating a collective anxiety regarding the future, and instilling a desire for change. Moreover, competition has become increasingly party-based since Japan adopted the mixed system. The opposition has further taken advantage of this atmosphere, and has blamed the then ruling party and the incumbent Mr. Yuya Niwa for causing the public’s worry, making voters feel that if they do not want to continue this policy, they should vote for the opposition and the challenger to stop it. In other words, the challenger has successfully made the health care issue sufficiently compelling to mobilize the voters who have for a long time supported the incumbent to switch their allegiance and support her and thereby stop the policy.