Competition for Power: Party Switching as a Means for Changing Party Systems in Japan

Since 1993, Japan has experienced party breakups, mergers and the formation of new parties that are rare in industrial democracies. As a result, the one-party dominance by the Liberal Democratic Party (LDP), with perennial opposition parties, has evolved into a LDP-centered governing coalition faced with the Democratic Party (DP) contending with it for office. While an electoral system change took place at the same time, party switching by legislators has led to a changing balance of power among parties, especially between the LDP and the DP. Especially since 1996, when the first election under a new electoral system took place, both the LDP and the DP have continued to attract switchers from other smaller parties and to increase their size. The LDP’s size has exceeded the threshold for a majority, but the party has not been able to attract a sufficient number of party switchers to achieve a majority that would enable it to pass legislation without allying with other parties. In contrast, the DP has become even more challenging to the LDP. The paper argues that party switchers have different prospects for future party systems. More specifically, switchers to the LDP believe that the LDP will restore one-party dominance to office. The switchers to the DP count on the DP’s advantage as a centrist party at the expense of the conservative LDP. The paper demonstrates the possibility that legislators may decide to switch, based on different assumptions of party competition, that is, office-seeking and policy-seeking when the power balance of parties is susceptible to changes.