Sanseitō Makes a Splash: Populist Politics on the Rise in Japan

A Murky Time for Japanese Politics

The July 20 election for Japan’s House of Councillors saw 125 of the chamber’s 248 seats up for grabs—half the total plus one vacant seat to be filled.

The stakes, though, were higher than suggested by the numbers. When the dust had cleared, the ruling Liberal Democratic Party had secured just 39 of the seats being decided—a slightly higher number than their all-time low of 36 seats in 1989, but still a drubbing that left it with 13 fewer seats than before the election took place. The LDP’s junior coalition partner Kōmeitō, meanwhile, lost 6 seats from its preelection total, winning just 8, in part due to the rapid dwindling and aging of the membership of the religious group Sōka Gakkai, which provides the bulk of its support.

The LDP-Kōmeitō coalition holds 75 of the upper house seats that were not up for election this time, meaning that the parties had to achieve Prime Minister Ishiba Shigeru’s modest target of 50 combined wins to maintain their majority hold on power in the chamber. Their record of 47 fell short of the mark, though, leaving them in a diminished position in the House of Councillors as well as the House of Representatives, where they became a minority government following the October 2024 general election.

The LDP, which celebrates the seventieth anniversary of its founding in November this year, has never in all that time been a member of a minority government in both houses of the Diet until now. This means Japanese politics has entered uncharted territory.

Following a spate of political money scandals up through the early 1990s, Japan sought to refresh the scene by shifting in 1994 from an electoral system of multimember districts to one with a combination of single-seat districts and proportional-representation bloc voting. The aim was to achieve a framework supporting two powerful parties that could wrest power from one another as the political winds shifted. This represented a break from the previous reality, where any problems that might crop up could be done away with by replacing one set of LDP leaders with another, in an ersatz form of regime change. And it did, in fact, eventually lead to a different group, the Democratic Party of Japan, stepping up to take the reins of power in 2009.

The 1994 reforms, though, left the House of Councillors largely untouched. Popularly considered less important than the powerful House of Representatives, this upper house had long offered less to voters in the way of meaningful actions on which to base voting decisions, and its actions in the political sphere tended to be swayed by the popular mood of the time. This introduced a degree of unpredictability, and there were numerous cases where prime ministers were pressed to step down following unexpected electoral shifts in House of Councillors contests.

This month’s election may end up in this category. Generally speaking, though, the natural way of things is for a ruling party that has fallen out of favor with the electorate to see its seats go to an opposition party, which gains influence in its place. This time, though, we have seen no simple transfer of seats from the LDP to an alternative: Rather, the anti-LDP vote has been split across numerous options, producing a crowded field of diverse opposition forces.

Two opposition parties making marked gains in the July 20 election are the DPFP, or Democratic Party for the People, which won 17 seats to bring its total in the upper house to 22 (up from 9), and Sanseitō, which took 14 seats to bring its total to 15, up from just 2. The largest opposition party in the chamber, the Constitutional Democratic Party of Japan, saw no change in its total seats, winning 22 seats to stay at 38. On paper these parties would seem to have the numbers to make an impact as a unified opposition, but politically speaking they range from the DPFP and Sanseitō on the right to the CDPJ on the left, leaving little room for cooperation. The stage is therefore set for fluid, unpredictable dealings on both the minority ruling and fractured opposition sides of the aisle.

Going to Extremes?

Many expected Sanseitō to be little more than a flash in the pan going into this election. But even as it trotted out its exclusionary “Japanese first” slogan, the party was running relatively unknown candidates in districts across the nation, and placing them near the top in the voting in many of them. This signals a turning point in Japanese politics, I believe. If we are to describe the 2025 upper house election as “historic” in some way, it will likely be not because it saw a sound defeat for the ruling LDP, but because it marked the serious rise of right-wing populist forces in Japan, a trend seen in various Western nations in recent years.

Kamiya Sōhei, Sanseitō’s leader, founded the party in 2020. Prior to that he had served in the Suita municipal assembly in Osaka Prefecture and unsuccessfully run for seats in the National Diet (with LDP backing) and the Osaka Prefectural Assembly. His political career languished until he began building a name for himself online, with antivaccination screeds on his YouTube channel. In the 2022 House of Councillors election he rode this momentum to a seat in the Diet, gaining the first foothold for his new party.

At its core, Sanseitō is a nationalist, restorationist political force on the far right of Japan’s political spectrum. In May this year it released its draft of a “New Constitution of Japan,” defining the state as one in which the emperor reigns over a unified polity of the imperial house and the people. The document also lists “the spirit of cherishing Japan” as one requirement for the people, and can be read as allowing for the stripping of citizenship from those who fail in this regard.

The Sanseitō draft constitution further demands that the people honor the Imperial Rescript on Education, promulgated in 1890 by Emperor Meiji, and goes so far as to position the cultivation of rice, “Japan’s staple food,” as a central part of food policy. In its clause commanding media organizations to fulfill their duty to “report on national policy fairly and without bias,” it comes across as little different from basic laws seen in authoritarian states like China or Russia.

The Sanseitō candidate Saya, a jazz vocalist who goes by a single name, came in second in the July 20 election in the Tokyo district, winning her seat with some 670,000 votes. She was formerly one of the “Tamogami girls,” high-profile supporters of Tamogami Toshio, who made a foray into politics after his 2008 dismissal as chief of staff of the Air Self-Defense Force for publishing an essay claiming that Japan was not an aggressor, but had been tricked into fighting in World War II by the Chinese and Americans. On July 3, soon after campaigning kicked off, Saya appeared on an Internet broadcast where she stated that arming itself with nuclear weapons would be “the cheapest way for Japan to defend itself” going forward.

Russian Influence Comes to Japan at Last

Sanseitō has staked out a series of extremist positions, as outlined above, gaining rapidly rising levels of attention for them via its use of social media. During the election period, this even led to accusations that the party had support from Russian information operations after Saya appeared in a program broadcast by the Japanese edition of Sputnik, the Russian state-operated online news channel. The European Union has suspended broadcasting activities by Sputnik in EU territories, describing it as a propaganda outlet.

Foreign information manipulation and interference, or FIMI, has been noted in Japan’s White Paper on Defense as a potential threat to the integrity of the country’s elections. FIMI was recognized as a factor as long ago as 2016 in Britain’s Brexit referendum and the US presidential election that sent Donald Trump to the White House for the first time. Now, nine years later, its impact appears to have reached Japan as well.

Analysts have explained Sanseitō’s success as due in part to its ability to peel off the LDP’s “bedrock conservatives” who once supported Prime Minister Abe Shinzō when he headed the party. While this has no doubt played a part, it pales in comparison to the larger issues of rising consumer prices, stagnant wages, and the perceived ineptitude of Prime Minister Ishiba Shigeru. Without these factors in play, there would have been no boom in popularity for Sanseitō.

According to the Comprehensive Survey of Living Conditions released by the Ministry of Health, Labor, and Welfare on July 4, fully 28.0% of households reported “very difficult” conditions this year, a rise of 1.5 percentage points from the 2024 survey. Indeed, Japan’s rate of inflation rests near the highest level among all developed economies.

For the people of Japan who sense their standard of living in decline—particularly those under age 40 in more precarious career positions—this malaise has been paired with the sight of constantly growing crowds of free-spending foreign tourists and news on wealthy overseas investors buying up real estate in Japan. Sanseitō’s “Japanese first” messaging has tapped into this discomfort, creating a chemical reaction of sorts that boosted the party’s fortunes in the upper house election.

Politics that aims at pressure points like these can be described as little other than populism. Rising prices in Japan can largely be ascribed to the policies of Abenomics, which reduced the value of the yen on exchange markets. But there is no debate that looks squarely at this underlying reason. And meanwhile, we see Sanseitō attracting crowds estimated upward of 20,000 to its final campaign rally in the Tokyo city center earlier this month.

Late in the evening on election day, Prime Minister Ishiba noted his intention to remain in office, fulfilling his duty as head of the largest party in the House of Councillors, a status his LDP did manage to hold on to despite its drubbing. Even if his party rejects this course and decides to hold a presidential election to replace him as party head, there is no guarantee that the new president will be duly selected by the Diet as the next prime minister, though. And whether it is Ishiba or someone new in office, he will face the same dismal reality of a ruling coalition without a majority of seats in either of the Diet’s chambers. The upshot? Japan is in for a prolonged period of aimless political drifting, with no clear way out.

(Originally published in Japanese on July 21, 2025. Banner photo: Sanseitō leader Kamiya Sōhei speaks to journalists in Shinjuku, Tokyo, on July 20, 2025, as the day’s election results come in. © Jiji.)