Japanese prime ministers and party leadership

This article shows what were/are the features of Japanese prime ministers as party leaders, as well as how and why these features have changed over the last 20 years. It focuses on three dimensions: party centralisation, internal cohesion and leadership security. On party centralisation, the electoral reform of 1994 introduced a single-member district system into the House of Representatives, or Lower House. This reform ended intra-party competition within the LDP that had existed under the multi-member system and since then the party has become much more centralised. On internal cohesion, the electoral reform has provided the prime minister with a powerful instrument to control the party: the power of endorsement. On leadership security, prime ministers like Koizumi Junichirō and Abe Shinzō were successful in restraining rebels and securing their leadership by effectively using the power of endorsement along with the power of appointment. However, a considerable number of prime ministers in the 21st century have had short tenures of about one year. While the personalisation of politics has made the position of popular prime ministers more secure, it has made unpopular prime ministers highly vulnerable.