Japan’s July 2025 Upper House election delivered a humiliating drubbing to the long-dominant center-right Liberal Democratic Party (LDP). The LDP failed to defend 13 seats and gained only 39 out of 124 contested, while its junior coalition partner Kōmeitō also suffered losses, leaving an LDP-led government with minority status in both Houses for the first time in history. In contrast, the most significant gains were made by a five-year-old fringe party, Sanseitō, which increased its strength in the House from one to 15 seats.
Sanseitō, which got its start on Youtube, is arguably the first successful radical-right populist party to emerge in contemporary Japanese politics. Staunchly conservative, if not “extremist” and “xenophobic,” its rise to prominence has caused an uproar in the global press. Japan, long perceived as impervious to the populist wave that has swept across the world, seemed to be following the trajectory of other developed democracies in which illiberal forces are on the rise.
The simultaneous decline of the LDP and the rise of a populist challenger to its right is the latest evidence of the wider unraveling of the postwar liberal order. For many decades, Japan’s democracy was the cornerstone of this order in East Asia. It embodied the stability that system promised, underpinned by uninterrupted LDP rule, economic prosperity, and security under the US nuclear umbrella.
“Prolonged stagnation and demographic crisis have cast doubt on its economic future.”
While Japan remains a staunch advocate of multilateralism, free trade, and rule-based diplomacy, even as Washington’s own commitment falters, its postwar model has been under strain. Since the 1990s, prolonged stagnation and demographic crisis have cast doubt on its economic future, and its security has been shaken by US retrenchment, Donald Trump’s transactional foreign policy, intensified US-China rivalry, and the unresolved North Korean threat. In this light, Japan offers a telling measure of the crises confronting democracies worldwide, and it is unsurprising that the new challengers to the LDP-led status quo are now also calling into question the liberal order it represents.
Japan has seen a number of challengers rise up over the past three decades. A long-standing disaffection with status quo politics, declining partisanship, rising distrust in politicians, and a bleak outlook on the future, particularly among the young, have fostered a permanent latent demand for political alternatives. Sanseitō, together with a group of other minor parties that made gains in this election, is the latest manifestation of these trends. Feeding into the anxieties about spiking consumer prices and wages that fail to keep pace, it rallied the disgruntled and politically inexperienced. Exit polls revealed that voters disapproving of the government and people in their 30s and 40s were more likely to vote for it than any of its competitors.
Yet, Sanseitō’s predecessors mostly proved to be little more than fleeting fads. Elite-driven, they often lacked a source of appeal beyond their charismatic leaders and were unable to cultivate a grassroots base that could keep them afloat. Sanseitō’s profile suggests that it may leave a more enduring—and disruptive—imprint on Japan’s political system and democratic institutions.
“Sanseitō’s predecessors mostly proved to be little more than fleeting fads.”
Historically, Japan’s political landscape has been marked by an absence of ideological polarization, with class and regional conflicts further dampened by pork-barrel spending. A predominantly centrist and apathetic electorate is averse to protest and other forms of political participation, and nearly half of the voters regularly choose to abstain.
In addition, the LDP has been effective at co-opting and neutralizing its challengers’ agendas. Former Prime Minister Abe was particularly adept at this strategy: He took up social policies, such as child allowances and gender-equality measures, from the liberal opposition, while also paying lip service to the right-wing nationalist vision pursued by organizations like the lobbying group Nippon Kaigi, which seeks to revise the constitution to allow Japan full military capabilities and restore elements of pre-war imperial ideology. The LDP’s flexibility has made it difficult for populist parties to set themselves apart from the establishment.
In this environment, more radical right-wing ideas were mostly confined to online platforms such as 2chan and later Twitter/X. Sanseitō brings them out into mainstream politics. Its platform is an exercise in calculated provocation, testing the limits of acceptable political discourse and freely borrowing from the playbook of successful populists elsewhere. Its slogan, “Japanese First,” directly echoes Trump’s campaign in the United States, and its representatives paint a picture of a nation whose sovereignty and future are threatened by self-interested elites, external conspiratorial forces led by international financial capital, and an influx of migrants.
Sanseitō’s initial surge was powered by a potent blend of conspiracy-laden narratives, spearheaded by its founder and leader Kamiya Sōhei, who cultivated a following on YouTube with content that included invocations of the “hidden powers that rule the world” and the “awakening of cosmic consciousness” and the question: “Was Hitler really a great evil?” Its fiercely anti-vaccination and anti-masking stance secured the party and Kamiya an Upper House seat in 2022. Two years later, the party added three more Lower House seats to its victory list.
In the latest election, Sanseitō drew attention by rallying against the excesses of globalization and immigration, aggressively challenging the elite consensus that a foreign workforce and tourism are indispensable to ensure the future of a super-aged nation. The party’s hyperbolic claims about immigrant crime rates and welfare abuse succeeded in making immigration—for the first time—into the focal point of the election despite the relatively low share of foreign residents in the population (just 3 percent).
Sanseitō has also forced other taboo topics into the mainstream political debate with its appeals to nostalgic nationalism. Its leaders criticize gender-equality policies for eroding family values and forcing women to prioritize work over childbirth, and promote educational reforms designed to cultivate historical self-respect. In line with this idea, Sanseitō’s electoral posters portrayed its leaders as direct successors of kamikaze fighters on a mission to protect Japan. Going further, its draft of a new constitution, unveiled shortly before the election, represents a stunning repudiation of postwar liberal democratic norms.
Borrowing from the Imperial Constitution, both in language and in spirit, it emphasizes “nation” over “individual” and “duties” over “rights,” elevates the status of the Emperor, and removes articles on popular sovereignty and pacifism, the key principles of the postwar Japanese state. While this draft echoes past efforts to craft a constitution “more suitable for Japan” and carries forward ideas from the LDP’s 2012 reform proposal, unlike earlier partial revisions that largely upheld the postwar constitution’s foundational principles and democratic tenets, it may be the first bid by a parliamentary party to fully overhaul them.
It is hard to say to what extent Sanseitō’s platform aligns with the preferences of the electorate. Although just a small fraction of voters prioritized the immigration issue in the election or hold radical right views, its stance on this issue made clear that it offers a distinctive alternative, clearly setting it apart from the status quo. At the same time, it was able to siphon votes from the LDP, whose conservative supporters felt alienated amidst the power vacuum on the right-wing flank of the party left by the assassination of Abe and the demise of his faction.
Sanseitō has set itself apart by utilizing the mobilization capacity of digital platforms, conducive to the spread of extreme and conspiratorial ideas, to develop an actual organization offline. Kamiya built recognition as a YouTuber, and Sanseitō’s own YouTube channel has more subscribers than any other parliamentary party in Japan. Unsurprisingly, over half of its voters in the recent election used social media and video streaming platforms as the primary source of information when deciding how to vote. Sanseitō’s initial online following was used for membership recruitment, and by the end of 2024, it reported having 75,000 members, exceeding Ishin, the third-largest party in parliament.
According to Shinohara Jōichirō, a former Communist Party staff member and one of Sanseitō’s founders, who is credited with developing its organizational structure, the party’s organization is inspired by Kōmeitō and the Communist Party. These parties are distinguished by a high level of member engagement and robust financial base, where the largest share of revenue is generated by selling party newspaper subscriptions. Similarly, Sanseitō adopted a digital subscription model, sending a daily newsletter and study materials to its fee-paying members. These fees, which are three to seven times (depending on the membership type) higher than the LDP’s, generate the largest share of Sanseitō’s income, making it independent of public subsidies.
Sanseitō has also been active in running offline awareness-building campaigns with meetings and talks all around the country that provide an actual place for member socialization, helping to foster a sense of common identity and party allegiance among them. The party has also invested in physical infrastructure and opened branches in every electoral district. Enabling operations on the ground, they contributed to its election of 155 local assembly members and allowed it to field the second-largest number of candidates after the LDP in the latest election.
Sanseitō’s future will hinge on the fickle mood of unaffiliated voters who brought about its success this time. Few challengers have succeeded at making this sector of the electorate turn out consistently. Moreover, anti-system parties have found it hard to maintain their radical profile once they become part of the system themselves. A fragmented parliament with a minority government, whose functioning will depend on consensus-building and cooperation between the opposition and government blocs, might be a particularly adverse environment to navigate. Similarly, elections to the more influential Lower House with its restrictive electoral system for minor actors also poses a high hurdle for challengers’ repeated success.
Only a few challenger parties in Japan have managed to outlive the popularity of their leaders. Sanseitō’s path will also depend on whether it escapes the curse of charismatic leadership by establishing an identity and organizational practices independent from Kamiya. But regardless of its ultimate trajectory, Sanseitō has already left its mark on Japanese politics. Having brought radical-right and conspiracy-laden narratives from the digital fringes into the very heart of national electoral politics, it has expanded the set of discourses acceptable in the mainstream, normalizing a rhetoric that questions the basic principles underlying the postwar order.
“Sanseitō has already left its mark on Japanese politics.”
Sanseitō’s breakthrough is a response not only to domestic grievances but also to a global moment in which the liberal international order and the established parties that represent it are losing ground amid the economic discontent of globalization’s “losers,” legitimacy crises in international organizations, and the waning credibility of US leadership. For Japan, whose political establishment remains among the most steadfast champions of this order, the challenge is especially acute.
To preserve itself and reinforce the stability it has enabled, Japan’s establishment must reclaim ideological ground ceded to the populist right, address genuine socio-economic as well as geopolitical insecurities, and re-engage a disillusioned public by offering compelling alternative narratives, and adapting to the new mediascape. Reduced to minority status, the LDP may be poorly positioned to accomplish these tasks. Yet, continued failure to do so risks placing Japan on the same path as other democracies where the erosion of consensus has transformed political culture in ways that may be difficult—if not impossible—to reverse.