TOKYO - A flagship political reform bill championed by the Japan Innovation Party is poised to test the JIP's year-old coalition with Prime Minister Sanae Takaichi's Liberal Democratic Party, with its passage through parliament far from assured despite backing from the premier.
The bill could cut 45 seats in the 465-seat House of Representatives, Japan's lower house, but it has come under a sustained pushback from opposition parties whose support Takaichi may need for separate legislation to cut the consumption tax. She has promised to honor the coalition agreement to pass it, aiming to do so in the current Diet session scheduled to run through Dec. 12.
The coalition accord, reached on Oct. 20, 2025, was key to Takaichi taking power as prime minister. The parties have moved closer together in the year since, with a JIP member taking a Cabinet ministerial post in September. A series of laws, including to select a "second capital," have been enacted despite the coalition's lack of a majority in the Senate, or the upper house of parliament.
Parliamentary arithmetic and slipping support rates for Takaichi's Cabinet mean the LDP and the JIP need each other in the immediate term. But the presence of other possible coalition partners and the JIP's push for more radical policies are leading some analysts to say that their ties are more fragile than they appear.
Rintaro Nishimura, senior associate at business advisory firm The Asia Group, said he is "not convinced this is a stable coalition," with the disparity in power between the two parties likely to become more visible.
Led by Osaka Gov. Hirofumi Yoshimura, the JIP shares the LDP's conservative positions on the constitution and national security, while diverging in its focus on reforms to the political system such as cuts to elected representatives.
While the parties have been able to paper over their differences in the last year, Nishimura said, "the more that the JIP compromises" due to its new Cabinet responsibilities, "the more it gives the LDP reason to be able to say they'll come along" and fall into line.
Such a development could stoke division in the junior partner's ranks, he said.
The push for a slimmer lower house has been at the heart of the JIP's agenda, presented as a must-do item for the ruling coalition.
Opposition parties moved to jointly boycott Diet deliberations over the seat-cut bill in the previous session, causing delays to other bills and posing a major parliamentary challenge to Takaichi. The current version, meanwhile, targets only seats filled under proportional representation, which opposition parties fear would put them at a disadvantage.
Apparently wary of a similar outcome in the current shorter Diet session, some LDP members have hinted at compromising on the number of lower house seats in the bill, which would automatically cut 45 seats if a lower house cross-party council fails to reach an agreement on electoral reform within a year of the law taking effect.
The bill "must advance in a way that all parties can agree on," LDP Secretary General Shunichi Suzuki told reporters earlier this month, suggesting a reduction of 31 seats based on Japan's shrinking population. He later retracted the remarks.
Executive Acting Secretary General Koichi Hagiuda, too, has said the party is approaching the bill with 45 "as a given," while not discounting a lower number.
A population-based cut has been advocated by the opposition Democratic Party for the People, the right-leaning group favored by some in the LDP such as party kingmaker and former Prime Minister Taro Aso -- himself an instrumental figure in Takaichi's rise.
Ayumu Nakai, a professor of politics at Kyoto Sangyo University and an expert on the JIP, pointed to its history of gradually cutting seats in the Osaka Prefectural Assembly, where it has reduced them from 109 in 2011 to a planned 73 in 2027, to suggest the JIP could yet have room to compromise.
"The party may not be completely satisfied, but it will be able to say the reduction happened because of it," he said, noting the JIP "had already halfway resigned itself to giving up its dream of a nationwide political party when it accepted becoming the LDP's junior partner."
While it quadrupled its seats in the 2021 lower house election to become the third-largest party, the JIP's progress has since stalled, and its support has remained concentrated in western Japan's Kansai region.
Approaching major elections, starting with next spring's unified local elections, are likely to pressure the alliance. Unlike the 26-year LDP-Komeito coalition that ended last year, the JIP and the LDP do not have an electoral cooperation pact.
Analysts said a poor showing for the ruling parties in local elections, or strong results for the LDP in 2028's upper house elections, could fuel questions in Takaichi's party about keeping the relationship going.
The coalition's roots come from bringing Takaichi to power, creating strong personal relationships between the JIP's leaders and the prime minister that have yet to spread widely within her party.
Nakai called the current alliance "a Takaichi-JIP coalition."
"Were Takaichi to lose power, a new LDP leader could win the presidential race by promising to end the coalition and do a deal with the DPP," he said.
