Structure or Agency? Understanding the Changes in Japanese Executive Leadership

While Japan is often described as a country with a stable dominant party system, the Japanese Prime Ministers were traditionally seen as weak, with leaders being replaced at a much higher rate than in the West (Elgie 1995; Mulgan 2004). The Koizumi and Abe premierships, however, seemingly bucked this trend as they became the two longest Japanese Prime Ministers in the Post-War era. What could be the explanation behind the increased longevity of the Japanese Prime Minister? Has the political environment (structure) been made more favourable by the recent reforms, or have these political leaders (agency) been more gifted? The historical and political traditions of the country can easily lead us to seek answers through analytical concepts from the British discourse on the core executive (Elgie 2012; see Dobson et al. 2023; Shinoda 2023), such as presidentialization (Poguntke-Webb 2005; see: Krauss–Nyblade 2005; Mishima 2019), prime ministerialization (Dowding 2013), and prime ministerial predominance (Heffernan 2003, 2005; Bennister 2012 see: Burrett 2017). Mark Bennister and collegues (2017; see also: Bennister 2023) have developed the Leadership Capital Index (LCI) from this theoretical framework as a diagnostic tool, measuring the amount of political authority and resources a leader has at a certain point in time. LCI makes it possible to examine not only the changing fortunes of a leader over time but also promises to make leaders comparable across different political systems. So far, the LCI only saw limited application on the Japanese Prime Ministers, with studies focusing on static, total LCI scores (Burrett 2016) or changes in very short timeframes (Maruoka–Rose 2023), losing some of the dynamic elements the method could offer. The method itself also has its own limitations. Firstly, whether the results of the LCI in differing political systems is actually comparable or not is still up for debate. Secondly, some of the LCI scores are based on expert opinion, and the small number of these experts giving the scores exposes the results to a high degree of variance and bias. Furthermore, while the LCI pays a great deal of attention to the perceived individual qualities of leaders, such as political/policy vision or communication skills, as well as political outcomes (e.g., policy and legislative performance), the role of the institutional context and its possible changes receive less attention. This is an area where the literature on the LCI should be expanded upon. Through the Japanese case, the paper attempts to rethink these conceptual and theoretical problems.