Tokyo, September 2025 — With Prime Minister Shigeru Ishiba stepping down, Japan now faces the task of finding a new leader at a time when its politics are more fractured than usual. The ruling Liberal Democratic Party (LDP), long the dominant force in post-war Japan, no longer commands a majority in either chamber of parliament, making the succession process more unpredictable than in the past.
Step One: The LDP Leadership Race
The immediate task is for the LDP to choose its next president a position that usually, though not always, leads directly to the prime minister’s office. The timetable for the leadership contest has not yet been set, but the process is familiar.
In the last race, held in September 2024, candidates needed at least 20 nominations from LDP lawmakers to enter the contest. The campaign involved weeks of speeches, debates, and hustings across the country, culminating in a vote split between party lawmakers and rank-and-file members. That race produced nine contenders, with Ishiba eventually emerging as leader after a run-off.
If the same rules apply, each lawmaker will cast a vote, with rank-and-file members collectively holding an equal share in the first round. A candidate winning outright becomes party president. If no majority emerges, the top two face a run-off, where lawmakers again vote, but the voice of grassroots members is reduced to 47 ballots one for each prefecture.
Step Two: The Parliamentary Vote
Winning the party presidency, however, does not automatically guarantee Ishiba’s successor the premiership. With the LDP and its coalition partner lacking a majority in both chambers, the outcome will depend on parliamentary arithmetic and, potentially, backroom alliances.
The lower house, the more powerful of the two chambers, votes first. Any member can be nominated, though historically, party leaders are the main contenders. A simple majority secures victory; if no candidate crosses that threshold, a run-off takes place between the top two.
The upper house then holds a similar vote, but only lower house members are eligible to serve as prime minister. If the two chambers cannot agree, the constitution gives the lower house the final word. This last happened in 2008, when the lower house backed the LDP’s candidate despite the upper house siding with the opposition.
Alliances and the Road Ahead
Japan’s political history shows how unpredictable these moments can be. In 1994, the LDP struck an unlikely alliance with the Japan Socialist Party once its fiercest rival to return to power, even allowing Socialist leader Tomiichi Murayama to become prime minister.
Given today’s fractured parliament, similar compromises cannot be ruled out. Whoever emerges as the next LDP president may seek new coalition partners or, alternatively, call a snap election to secure a mandate from the public.
What is clear is that the process will not only decide Japan’s next leader, but could also reshape the balance of power in a country navigating economic challenges, regional security threats, and the pressures of an aging society.
