Don’t Underestimate Sanseito

Prior to Japan’s upper house election on July 20, it was difficult to fathom how a political party that has doubled down on conspiracy theories surrounding vaccination, spread unsubstantiated claims rooted in pseudoscience, and proposed a draft constitution that erases language resembling universal values (including basic human rights) could ever win a Diet seat. The idea that such a party could become a viable force in contested electoral districts seemed even more far-fetched.

However, Sanseito, a far-right – some have used the term “ultranationalist” – populist party, proved that such a feat is possible.

Carrying the banner of “Japanese First,” Sanseito shocked the nation by winning 14 seats in the House of Councillors election. This success was fueled by a surge of over 7 million votes in the proportional ballot – earning Sanseito the second-largest vote share among opposition parties – and by securing seats in multi-member electoral districts, defeating well-established parties.

Typically, newly formed parties in Japan perform well in urban areas, where independent voters are more prevalent. Sanseito reflected this trend by winning seats in Tokyo and three neighboring prefectures that make up the Greater Tokyo Area. However, the party also demonstrated strength in rural regions.

The starkest example of this trend occurred in Gunma Prefecture, a longstanding stronghold for the Liberal Democratic Party (LDP). Over the past half century, three prime ministers and their offspring have held seats in Gunma. Within this political landscape, Sanseito nearly defeated the incumbent by capturing a substantial share of conservative votes.

Responding to this development, Sato Osamu of Nikkei Shimbun opined, “It is a historic event that a conservative party has emerged with such a strong base to take away the support of the Liberal Democratic Party.”

One important – though often overlooked – factor that may have contributed to Sanseito’s emergence was its appeal to the “mainstream.” While Sanseito was not a brand-new party – it had been established five years earlier – it remained relatively unknown, as its activities were largely limited to online broadcasts and town meetings organized for its rank-and-file members. In other words, it operated on the fringes. However, when Umemura Mizuho – a former upper house member with Nippon Ishin no Kai, who left that party after losing a primary election – joined Sanseito, the party became eligible to participate in nationally televised debates. This likely added a degree of credibility to its public image.

Additionally, during media appearances, party leader Kamiya Sohei has actively deflected accusations of misogyny and xenophobia, which can be seen as an attempt to position the party closer to the political center.

It is also worth noting that Sanseito’s meteoric rise cannot be explained solely by its success in courting the conservative vote. Prior to the election, Furuya Keiko, a political analyst and director of the Reiwa Institute for Political and Social Affairs, wrote that the party’s core supporters were individuals previously uninterested in politics – most of whom had never voted before and lacked emotional investment in any particular party. One exit poll showed that Sanseito was a close second to the Democratic Party for the People (DPFP) with the most support among independent voters, suggesting that its appeal – particularly its emphasis on nationalism and economic populism – transcends traditional ideological boundaries.

Some observers have predicted that Sanseito’s recent “buzz” will be short-lived. However, there is reason to believe Sanseito will not disappear like other nascent parties that have faded away quickly, given the groundwork they’ve laid. According to their website, the party claims to have 287 local branches – close to covering all lower house electoral districts. This extensive infrastructure rivals only a few parties aside from the LDP.

Sanseito’s party network was in full force during the election: they fielded candidates in every electoral district, defeating incumbents from both the ruling party and the Constitutional Democratic Party (CDP), the largest opposition. With their new electoral strength – amplified by free media exposure – the party is now in a stronger position to recruit new candidates and expand its already-established infrastructure.

In an interview with Sankei Shimbun, Watase Yuuya – who helped launch Sanseito but later resigned after the party began to embrace conspiracy theories – stated that the strength of the populist party lies in its identity as a “party member-centered organization,” which grants a high degree of autonomy to its members and their local activities. In one of his own columns, Watase also argued that Sanseito’s party structure differs markedly from other parties, as its primary priority is to recruit new members.

He further suggested that the rank-and-file of other parties tend to be less motivated than those of Sanseito, as they have less personal investment. In some parties, candidates typically inherit their electoral districts – many members of the LDP do – and in other cases, they are obliged to follow the directives of intermediary organizations they represent – the CDP and DPFP have labor unions as their main sponsor.

Kamiya, Sanseito’s leader, has suggested that their next goal is to secure 40 seats in the lower house election – a target that seems attainable given the party’s current performance and the political machinery at its disposal. Although there is still uncertainty as to whether they will revise their policy platform, which remains far from the mainstream – with calls for relocating foreign military bases, abolishing the consumption tax, enacting a new constitution, and passing a spy prohibition bill – they should not be underestimated.