Introduction

 

The 2025 Upper House election was officially announced on July 3 and subsequently held on July 20. The Upper House is comprised of 248 members who serve six-year terms without dissolution; half of the members, or 124 members, are elected every three years. The Upper House uses a mixed electoral systern, wherein 74 members are elected in each election from 45 prefectural districts (each with 1 to 6 seats), and 50 members are elected through a nationwide open-list proportional representation (PR) tier.

 

Election Results

 

Table 1 presents a synopsis of election results. The ruling Liberal Democratic Party (LDP) suffered a historic defeat, securing only 39 seats—a significant drop from the 52 contested seats it held before the election. This outcome represents the third-lowest number of seats secured by the LDP since its establishment in 1955. Despite the collaboration between the LDP and Komeito, the LDP-Komeito coalition managed to obtain a total of 122 seats, falling short by three seats from achieving a majority in the upper house (125 seats). Following their electoral setback in the October 2024 lower house election, the coalition has subsequently lost its majority in both the lower and upper houses. Komeito, the centrist party which has maintained a coalition with the LDP since 1999, also experienced a significant loss in its electoral success. The party secured a mere 8 seats in the parliament, making its lowest performance since its establishment in 1964. The aging of its supporter base has diminished its capacity to mobilize votes (Nihon Keizai Shimbun, July 20, 2025).

 

On the other hand, the three primary opposition parties encountered distinctly disparate outcomes. The Democratic Party for the People (DPP) demonstrated notable progress, expanding its representations from 4 contested seats to 17. By appealing to the working-age generation and pledging to increase take-home pay through income and consumption tax cuts, the DPP successfully expanded its support. Sanseito, a right-wing party founded in 2020, experienced a significant increase in its representation, rising from a single contested seat to 14. The “Japan First” platform and anti-foreigner policies which the party has advocated for have led to its emergence as a disruptive force in the electoral process.

 

Conversely, the Constitutional Democratic Party of Japan (CDP) experienced a stagnant support base, maintaining its hold on all 22 contested seats. Despite the LDP’s decline, the CDP was unable to garner support from disaffected voters, who instead opted to support the DPP or Sanseito. The Japan Innovation Party (JIP) experienced a modest increase in its representation, rising from 5 contested seats to 7. However, this growth was limited to winning seats in prefectural districts only within the Kansai region and did not translate into a broader nationwide political base for the party. The Japanese Communist Party (JCP) persisted its protracted decline, securing a mere 3 of its 7 contested seats. A similar situation is observed with the JCP, which, like Komeito, is confronted with a diminishing and aging supporter base. (Nihon Keizai Shimbun, July 20, 2025).

 

 

Figure 1 illustrates the total number of votes each party received in the PR tier, a more accurate indicator of national-level party support than prefectural district results, which vary with the presence and the number of a party’s candidates. In the PR tier, the LDP received 12,808,306 votes (21.6%), the DPP received 7,620,489 votes (12.9%), Sanseito received 7,425,053 votes (12.5%), and the CDP received 7,396,328 votes (12.5%). While the vote shares of the three primary opposition parties were relatively close, the robust performances of the DPP and Sanseito were particular noteworthy. A notable observation is that the CDP, the second-largest party in terms of total seats across both houses, lagged behind both the DPP and the right-wing Sanseito.

 

Figure 1. Total Votes Received by Each Party in the Proportional Representation Tier

 

According to Jiji Press’s exit polls, 26.8% of voters indicated that they did not express support for any particular political party[1]. Among the independent electorate, 14.5% (7.9% in the 2022 upper house election) cast their votes for the DPP in the PR tier, followed by 14.1% (26.0% in 2022) for the LDP, 13.6% (14.1% in 2022) for DPJ, 13.3% for Sanseito, and 8.1% (16.9% in 2022) for JIP. In contrast, among those who identified as LDP supporters, 75.2% casts their votes for the LDP, while 4.2% voted for Sanseito, 3.7% for the DPP, and 3.3% for the CDP. The LDP’s loss can be attributed to a decline in support from independents, while the growth of the DPP and Sanseito can be attributed to support from both independent voters and LDP supporters.

 

 

Major Issues in the Upper House Elections

 

According to Yomiuri Shimbun’s exit polls, the most salient policy concern for voters was inflation and economic policies (46%), followed by pensions and social security (17%), policies to address the declining birth rate and support for children (12%), immigration-related policies (7%), political reforms (5%), foreign affairs and national security (4%), and agricultural policy including rice prices (3%) (Yomiuri Shimbun, July 21, 2025).

 

With regard to the issue of inflation, all major opposition parties have pledged to reduce the consumption tax, while the ruling LDP and Komeito have rejected tax cuts and instead have proposed one-time cash transfers ranging from ¥20,000 to ¥40,000 per person. Among the opposition parties, the DPP campaigned on the promise of “increasing take-home pay” by reducing income and residential taxes. The DPP garnered significant support from the working-age demographic, particularly among voters in their teens and twenties (Nihon Keizai Shimbun, July 20, 2025). Conversely, apprehension regarding political funding scandals appeared to have diminished. While 9.2% of voters indicated that politics and money and political reform were the most salient issue in the 2024 lower house election, only 5% concurred in the case of this upper house election.

 

The election results provide several significant implications for Japanese politics. First, Japanese politics may potentially shift from majoritarianism to fragmentation. Since 1955, with the exception of brief periods from 1993 to 1994 and from 2009 to 2012, the LDP has been in power. With the exception of the periods from 1998 to 1999 and from 2007 to 2009, the LDP-led government maintained a majority in both houses of the Diet for the majority of these periods. The government was able to exercise a majoritarian style of governance, as it theoretically had the capacity to pass all bills and budgets without opposition support.

 

However, following the loss of its majority in the October 2024 lower house election, the LDP-Komeito coalition has encountered difficulties in passing legislation and budgets without the support from the opposition parties. For instance, during the 2025 ordinary Diet session, the LDP-Komeito government was compelled to revise the initial budget for the first time in 29 years in response to demands from the JIP. With regard to pension reform, the government co-sponsored bills with the CDP and ultimately adopted the CDP’s proposal to raise benefits in the National Pension Systern, which is funded by the Employee’s Pension Insurance reserve. Consequently, Japanese politics appears to be undergoing a shift from a majoritarian style of policymaking towards a more fragmented approach.

 

Second, anti-foreigner sentiment has emerged as a significant force in Japanese politics, while Japan has long observed anti-immigration movements in Europe and the United States from a distance. Sanseito, a recently established right-wing political party, explicitly campaigned under the slogan “Japanese First.” In its manifesto, the party called for the following measures: (1) limitations on the admission of unskilled foreign workers; (2) stricter requirements for naturalization and permanent residency requirements, including mandatory tests of Japanese language and cultural knowledge to assess loyalty to Japan; and (3) restrictions on foreign nationals’ access to public benefits such as health insurance, welfare, and scholarships.[1]. Sanseito obtained 14 out of 125 contested seats, including seven from prefectural districts and seven from the PR tier. This places the party in fourth position among all parties. Its future performance in national and local elections, as well as its potential influence on governance and policy, warrant close attention.

 

The slush fund scandal, first exposed in 2022, has persisted as a significant issue in the realm of Japanese politics. In Japan, political parties and factions frequently organize fundraising events, selling tickets to corporations, organizations, and private individuals. These events frequently take a symbolic form, with a significant number of tickets being purchased by individuals or organizations that do not physically attend the event. This practice effectively transforms the event into a form of political contribution. Within the LDP, factions required their members to sell party tickets to meet fundraising quotas. Revenues that surpassed these quotas were subsequently redistributed to individual members without being disclosed in official political finance reports. In essence, the term “slush funds” is used to describe the unreported transfer of funds from factions to their members.

 

The scandal had far-reaching consequences. The dissolution of five LDP factions (excluding the Aso faction) in 2024, Prime Minister Fumio Kishida’s decision not to seek re-election as party leader in August 2024, and the LDP’s loss of its lower house majority are all factors that must be considered when discussing the events that led to the dissolution of the LDP. In response to these events, both the ruling and opposition parties initiated a series of political finance reforms. In June 2024, the Diet passed a series of bills that lowered the disclosure threshold for party ticket purchases from ¥200,000 to ¥50,000. This change in legislation resulted in the disclosure of even minor purchasers who had previously remained anonymous.

 

In December, further reforms were enacted, including the abolition of policy activity funds, which were distributed from parties to their members without any requirement to disclose their use. Additionally, an independent oversight body was established within the Diet to monitor political finance. The reforms also included a ban on ticket purchases by foreign nationals, and a mandate to digitize political finance reports. Nevertheless, proposals to prohibit corporate and organizational donations were not adopted, thereby leaving key issues unresolved.

 

A total of 82 LDP members were found to have received slush funds, including 51 lower house members and 31 upper house members. Of the 31 upper house members, 18 faced re-election in 2025. 13 subjects were reinterviewed, while 5 were not. Furthermore, two former members of the lower house also ran. A total of 15 individuals who have received slush funds were subsequently apprehended: 10 in prefectural districts and 5 in the PR tier. Of the 10 district candidates, only three received endorsements from the LDP’s coalition partner, Komeito. In the election, eight of the ten district candidates were elected, while only two of the five PR candidates won seats. The electoral consequences of the slush fund scandal appear to have been mixed. Preliminary reports from news outlets have indicated that the electorate exhibited a pervasive sense of mistrust in the aftermath of the scandal, thereby contributing to the LDP’s overall electoral losses.

 

It is also noteworthy that even the eight successful district candidates prevailed by narrow margins (Asahi Shimbun, July 21, 2025; Mainichi Shimbun, July 21, 2025). Concurrently, as previously mentioned, the proportion of voters who identified political finance scandals as the most pressing issue decreased from 9.2% in the 2021 Lower House election to 5% in 2025. Furthermore, the fact that 80% of district candidates were elected indicates sustained voter support. In the aftermath of the election, a number of LDP members who had received slush funds have called for Prime Minister Ishiba to resign, suggesting that the scandal may persist as a significant political concern.

 

Prospects of Future Japanese Politics after the Election

 

As of a few weeks after the election, the fate of Prime Minister Shigeru Ishiba remains uncertain. On election day, July 20, as media reports highlighted the LDP’s poor performance, some members called for Prime Minister Ishiba’s resignation. However, during a televised interview that evening, Ishiba declared his intention to remain in office, reaffirming it at a press conference the following day. On July 23, he engaged in deliberations with former prime ministers Taro Aso, Yoshihide Suga, and Fumio Kishida, subsequently reaffirming his resolve to continue in office. Nevertheless, there has been a steady increase in the number of calls for his resignation from both LDP legislators and local party organizations. On July 28th, at the LDP’s joint consultative meeting of Diet members on July 28, numerous legislators urged Ishiba to resign. However, Ishiba reaffirmed his intention to remain in office.

 

Given the LDP-Komeito coalition’s loss of majority in both houses, the selection of a new prime minister might not necessarily resolve the prevailing political deadlock. It is probable that the ruling parties will continue to encounter challenges in maintaining their position of authority power and successfully passing legislation. Even if a new lower house election were to be held, there is no guarantee that the coalition would regain a majority in the lower house. Moreover, even if it were to regain a majority in the lower house, it would still lack a majority in the upper house, which would complicate the legislative process. Furthermore, the opposition parties have thus far declined the prospect of joining the coalition at this juncture. These dynamics suggest that Japanese politics is likely to remain in a state of uncertainty for the foreseeable future. ■

 

References

 

[1]https://www.jiji.com/jc/article?k=2025072100003&g=pol

[2]https://sanseito.jp/sanin_election_27_policy/

 

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■ Fujimura Naofumi is a Professor at the Graduate School of Law at Kobe University.

 

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■ Edited by Jaehyun Im, Research Associate
    For inquiries: 02 2277 0746 (ext. 209) | jhim@eai.or.kr