從自民黨總裁選舉制度分析自民黨派閥勢力的形成與消長

自民黨成立到二度下台爲止的約五十四年期間，除了短暫的二年三個月外，不論是自民黨單獨執政，或是組成聯合政權，自民黨的總裁同時擔任總理大臣，不僅是日本政治的最高領導者，而且掌握政黨與政府的龐大資源。自民黨政治家爲了爭奪總裁職位，集結成派閥，展開激烈的競合關係。因此，派閥勢力也成爲觀察戰後自民黨政治與日本政治的重要關鍵詞。既往的研究將「總裁選舉」視爲被解釋項，用派閥的競合關係解釋總裁選舉中由誰勝出。然而，本文研究發現，派閥是總裁職位爭奪的產物，而其勢力亦將隨著總裁選舉的變化而出現消長的現象。本文嘗試著從總裁選舉的實施過程中，對派閥勢力消長的影響，具有代表性的三個階段，亦即首屆總裁選舉、總裁初選制度的採用、第八十七屆的總裁選舉等時間點，論述自民黨派閥的成立，以及其勢力的消長，提供另一個觀察自民黨政治運作的切入點。

關鍵字

自民黨總裁；派閥政治；政治改革；政治決定過程；保守政治體制

並列摘要

In the fifty-four years before it lost power for a second time in 2009, the LDP president normally also served as prime minister and dominated Japanese politics, regardless of whether the LDP was in power alone or as part of a coalition government. The only exceptions were the cabinets of Morihiro, Tsutomu and Tomiichi (a total period of two years and three months). Since the LDP dominated the machinery of government, the president had control over both government resources as well as the party. LDP factions were formed with the purpose of winning the position of president. LDP politics was defined by conflict and cooperation between different factions as each group sought to maximize its own advantages.In previous research, the LDP presidential election, as a dependent variable, is highly connected with conflict and cooperation between factions. However, this article argues that factional politics is not a variable which explains the LDP presidential election, but rather is a product of the current electoral system. It also argues that the rise and fall of factions has a strong relationship with the outcome of presidential elections.From observation of three important phrases of the LDP presidential election-the first presidential election, the adoption of presidential primary election and the presidential elections after the 87th session-this article analyzes the formation, growth and decline of factions within the LDP, and tries to provide anew perspective on factional politics within the party.