Japan’s Sanseito Party has garnered massive public support amid anti-foreigner protests. Fueled by support (and its own promotion) for its anti-immigrant agenda, the party won a whopping 13 seats in the upper house of the Diet in the July 2025 elections.
Instability within Sanseito
A significant factor explaining the party’s decline is internal instability. Since its founding in 2020, the party has regularly lost members at the local and national levels. Such events are not uncommon in politics, but they should not occur with such frequency (and at such a level) in a “healthy” party.
In 2023, one of the party’s co-founders, Toshiaki Yoshino, left the party. The official reason given was ideological differences; however, some believe this decision stemmed from disagreement with the party’s decision-making process and leadership style. That same year, party adviser Kunihiko Takeda was expelled from Sanseito, also officially due to ideological disagreements.
The departure of even such high-ranking members demonstrates that the party is experiencing certain internal problems. These could be ideological differences, issues of management, leadership style, or party discipline. Regardless of the nature of the problems, this trend is extremely destructive, given the specific nature of the party. Each candidate has their own identity, their own brand, and their own constituency; most of them are “candidates from the people.” Therefore, the departure of such a candidate from the party leads to a loss of votes. Furthermore, such cases are increasingly being highlighted in the media, further damaging Sanseito’s popularity.
The LDP Borrows the Popular Rhetoric
Sanae Takaichi’s emergence as LDP President and Japan’s Prime Minister proved to be both timely and advantageous for her party. Takaichi’s positions on many issues align with those popular with a significant portion of the electorate and promoted by Sanseito, namely: increasing defense spending, restricting the admission of foreigners, and refusing to acknowledge Japanese war crimes during World War II.
The collapse of the LDP-pacifist Komeito coalition and the alliance with the Ishin no Kai Party lifted restrictions on Sanae Takaichi to change the defense budget, which the Prime Minister plans to increase to 2% this fiscal year. Sanae Takaichi also expressed interest in addressing issues with foreigners, albeit cautiously. On November 4, the first meeting of the new Ministerial Council on the Acceptance of Foreign Nationals and the Realization of a Society of Well-Ordered and Harmonious Coexistence was held. Judging by the Prime Minister’s instructions, the council is to discuss measures to combat illegal immigration and foreign crime, but also to address the adaptation and integration of foreign specialists, which Japan is currently in dire need of.
Thus, the LDP borrowed the most popular themes and slogans from Sanseito and demonstrated its intention to fulfill the citizens’ wishes related to them (while doing so carefully, so as not to alienate other segments of the electorate, such as those opposed to a purely xenophobic policy toward foreigners). Since the LDP is the largest party in the Diet (not holding a majority, but still extremely influential), and Sanseito is a numerically insignificant opposition group, it was entirely expected that voter support would shift toward a party that can actually change policy in the here and now.
During the Diet session on November 6, Sanseito leader Sohei Kamiya posed numerous questions and proposals to Sanae Takaichi: on tightening measures against foreigners, on increasing military spending, on increasing the focus on moral and patriotic education in schools, and on reviewing vaccine safety (on which Sohei Kamiya urges taking the Trump administration as an example). In my opinion, Sanae Takaichi gave Sohei Kamiya a good response, agreeing with most of Sanseito’s positions (but arguing with some, such as the vaccine issue) and pointing out that measures are already being taken to address most of these issues. In doing so, she demonstrated the approach I described above—accommodating popular positions while demonstrating that the LDP is already addressing the issues troubling society.
Shohei Kamiya did not stop there, and, perhaps in order to boost his party’s ratings and to attract attention to it, he again entered into a debate with Sanae Takaichi on November 13 at a meeting of the Budget Committee, intensifying his attacks on the Prime Minister, but without much success.
However, judging by the comments on the Sanseito YouTube video of the aforementioned November 6 Diet session, the party’s audience had already chosen the winner before watching the video: the overwhelming majority of comments are supportive of Sanseito, while many are critical of the LDP and Sanae Takaichi. This brings us to another interesting aspect of Sanseito.
Sanseito: a Cult of a Party?
Sanseito, unlike other veteran parties, built its initial audience primarily online; a significant portion of the party’s electorate consists of people previously uninterested in politics or disillusioned with it. The party’s unique channels of communication with its audience and the electorate itself, which Sanseito mobilizes through emotional appeal, contribute to the formation of a semi-closed information field. Within this field, Sanseito politicians convince their followers of the dangers of vaccines, conspiracies by political elites, and that Japan did not commit war crimes such as the Nanjing Massacre during World War II.
At the same time, voters who are not fully immersed in Sanseito’s ideological and informational landscape may be discouraged by media revealing the truth about the party’s statements and ideals, as well as its internal problems. It’s possible that the party’s popularity has declined, among other reasons, due to the opinions of these disillusioned individuals.
Conclusions
Sanseito represents an interesting example of a populist party that capitalizes on viral problems and momentary trends, creating a difficult-to-penetrate information landscape within which voters are fed unverified, and sometimes deliberately false, information. However, instability within the party, growing mistrust towards it, and the clever media maneuvers of the LDP and Sanae Takaichi pose serious challenges for Sanseito.
Tooru Yoshida, a political scientist and professor at Doshisha University, has put forward an interesting theory that new right-wing populist parties in Japan last about three years, after which they run into difficulties, lose support, and disband. It’s quite possible that Sanseito is heading toward a similar endgame, but now, at times of significant and unpredictable change in Japanese politics, I wouldn’t bet everything on its imminent demise in the near future.
Daniil Romanenko, a Japanologist researcher from the Institute of Oriental Studies of the Russian Academy of Sciences
Follow new articles on our Telegram channel
