1925年中選挙区制導入の背景

抄録

  In 1925 the Law of the election of the Lower House was revised, and the medium-sized constituency system was introduced. This system had been continued for about 70 years and given great influence to Japanese politics. Why and how was the medium-sized constituency system introduced in 1925? The aim of this paper is to answer this question.
  It has often been said that the three parties in power introduced it in order to escape from competing each other and to keep their base. This is the case, but the background was much more complicated. This paper focuses on three points.
  First, quite a few medium-sized constituencies had already been made when Hara Cabinet revised the Law of the election of the Lower House in 1919. It reflected wishes of Upper House, which was afraid of Seiyukai's mastery over Lower House, and wishes of some Seiyukai or independent MPs, who were afraid of changes of their constituencies.
  Second, the small-sized constituency system was greatly criticized among journalism and academic world after World War I. They insisted that corruption in election and higher cost for election was due to the small-sized constituency system, and they were generally welcome to proportional representation and multi party system in Europe. In 1923 Advisory Committee on Law expressed that proportional representation should be adopt. These voices promoted the review of the small-sized constituency system.
  Third, it was Kenseikai rather than three parties in power that took the initiative in introducing the medium-sized constituency system. Kenseikai did it in order to avoid returning to the large-sized constituency system, which was likely to make excessive multi party system, and to introduce the favorable election system to it. The medium-sized constituency system was favorable for Kenseikai in that it would not lose heavily. Kenseikai aimed to grow as one party in two party system, and the plan really came true after that.