Constitutional Democratic Party of Japan
Japanese political party
From Wikipedia, the free encyclopedia
The Constitutional Democratic Party of Japan (立憲民主党, Rikken-minshutō; CDP[10] or CDPJ)[11] is a liberal political party in Japan. It is the primary centre-left party in Japan, and was the second largest party in the National Diet behind the ruling Liberal Democratic Party (LDP).
Constitutional Democratic Party of Japan 立憲民主党 Rikken-minshutō | |
|---|---|
.svg) | |
| Abbreviation | CDP CDPJ |
| President | Shunichi Mizuoka[a] |
| Secretary-General | Masayo Tanabu |
| Founder | Yukio Edano |
| Founded | 3 October 2017 15 September 2020[b] |
| Split from | Democratic Party (2016)[b] |
| Preceded by | Constitutional Democratic Party of Japan[b] |
| Merged into | Centrist Reform Alliance (House of Representatives) |
| Headquarters | 2-12-4 Fuji Building 3F, Hirakawa-chō, Chiyoda-ku, Tokyo 102-0093, Japan |
| Newspaper | Rikken-minshu[4] |
| Youth wing | RikkenYouth[5] |
| Membership (August 2024) | 114,839[6] |
| Ideology | |
| Political position | Centre to centre-left |
| National affiliation | Centrist Reform Alliance (2026–present) |
| International affiliation | Council of Asian Liberals and Democrats (observer) |
| Colors | Blue[7] |
| Slogan | 政権交代こそ、最大の政治改革。 Seiken koutai koso, saidaino seijikaikaku.[8] ('A change of government is the biggest political reform.') |
| Councillors | 39 / 248 |
| Representatives | 0 / 465 |
| Prefectural assembly members | 231 / 2,614 |
| Municipal assembly members[9] | 730 / 28,940 |
| Election symbol | |
 | |
| Party flag | |
Alternative flag | |
| Website | |
| |
.svg)
It was founded in October 2017 as a split from the Democratic Party ahead of the 2017 general election, where it allied with the Japanese Communist Party and Social Democratic Party and overtook Kibō no Tō to become the largest opposition party. In late 2020, the party was re-founded following a merger with majorities of the Democratic Party For the People and the Social Democratic Party as well as some independent lawmakers. In the 2021 general election, it underperformed expectations and lost several seats. In the 2024 general election, the party surged and achieved the best result in its history, gaining 148 seats, up from 96 before. In 2026, it merged with Komeito in the House of Representatives to form the Centrist Reform Alliance in advance of the 2026 general election, however the party still caucuses as the CDP in the House of Councillors and in local elections. In the 2026 election, CDP-affiliated members of the CRA lost most of their seats, reducing the number of CDP-affiliated representatives from 144 to 21.
The party's platform supports raising the minimum wage, expanded welfare policies, the legalization of same-sex marriage, increased gender equality, renewable energy policies, decentralization, a multilateral and pragmatic foreign policy, the revision of the U.S.–Japan Status of Forces Agreement, tax reform and electoral reform. The party strongly opposes efforts to amend the Japanese Constitution to reinterpret Article 9 or codify the status of the Japan Self-Defense Forces and also opposes nuclear power.
History
Formation and 2017 election
The party was formed in the run up to the 2017 general election from a split of the centre-left wing of the opposition Democratic Party (DP).[12][13][14][15] Prior to the election on 28 September 2017, the DP House of Representatives caucus dissolved in order for party members to stand as candidates for Tokyo governor Yuriko Koike's Party of Hope or as independents in the upcoming election.[16]
The new party was launched on 2 October 2017 by DP deputy leader Yukio Edano at a press conference in Tokyo for liberals and left-leaning members of the DP who did not wish to, or were rejected for, contesting the election as candidates for the Party of Hope.[17][18]
On 3 October 2017, it was announced that the new party would not contest seats where former Democrats were running as Party of Hope candidates,[19] a gesture which was not returned when the Party of Hope ran a candidate in Edano's incumbent district. The Japanese Communist Party (JCP), in turn, pulled their own candidate from running in Edano's district so as to not take away votes from him.[20] The party won a total of 55 seats,[14] becoming the leading opposition party and leading the pacifist bloc (including the JCP and Social Democratic Party) to become the largest opposition bloc.
In July 2020, the CDP became an observer affiliate of the Council of Asian Liberals and Democrats.[21]
2020 merger and refoundation
On 19 August 2020, the CDP announced that it would merge with the majority of the Democratic Party For the People (DPP) as well as some independent Diet members in September of that year.[22]
On 10 September 2020, the new party elected Edano as leader and voted to retain the CDP name.[23] Following the merger, the new CDP had 149 members and held 107 seats in the House of Representatives, compared to 156 members and 96 seats held by the Democratic Party in 2016. The independents who joined the CDP in this merger included former Prime Minister Yoshihiko Noda. Several conservative DPP members, including DPP president Yuichiro Tamaki, did not join the CDP and instead continued to lead a rump DPP independent of the CDP.[24][25]
On 14 November 2020, the Social Democratic Party (SDP) voted to agree to a merger arrangement with the CDP, allowing SDP members to leave the party and join the CDP.[26] SDP leader Mizuho Fukushima was opposed to the merger agreement and as a result remained in the Social Democratic Party.[26]
The CDP contested the 2021 general election in an electoral pact co-operating with the JCP, Reiwa Shinsengumi and continuing DPP and SDP parties in fielding single opposition candidates in single-seat constituencies.[27] Edano resigned as party leader following the election on 2 November 2021, due to poorer than expected electoral results, in which the CDP fell from 110 to 96 seats.[28][29]
Kenta Izumi was elected as the leader of the CDP in the 2021 Constitutional Democratic Party of Japan leadership election on 30 November 2021. Formerly a member of the DPP, he said that the two parties are regarded by the public as "close" and "thought to be like brothers" and "expressed support for a tie-up" between the two.[35]
On 23 September 2024, former Prime Minister Yoshihiko Noda was elected party president on the party leadership election, with Junya Ogawa chosen as party general secretary.[36]
In the 2024 general election held on 27 October 2024, the CDP greatly increased their seat count in the House of Representatives to 148, depriving the ruling Liberal Democratic Party of their majority.[37][38]
2026 merger with Komeito
On 15 January 2026, CDP president Noda announced that the party had agreed to merge with Komeito in the lower-house to form the Centrist Reform Alliance.[39][40] Only a handful of members, including Kazuhiro Haraguchi, left the party in protest; the vast majority of lawmakers joined the new party as planned.[41] In the 2026 election, the CRA lost a significant number of seats, winning only 49 of them, while the LDP gained seats and secured more than a two-thirds majority of the lower house on its own. 21 CDP-affiliated candidates won seats, down from 144 before, while 28 Komeito-affiliated candidates won seats, up from 21 before.[42]
In the 2026 Japanese local elections, the CDP and Komeito will field their own candidates instead of a unified CRA banner. In addition, the parties have not merged in the House of Councillors.[43]
Ideology and platform
The CDP has been described as liberal[44][45][46] and social-liberal,[47][48][49] and in favour of constitutionalism.[50] The party has also been described as centre-left,[13][14][51][52][53][54] progressive,[46][55][56] and left-wing populist.[57] A study that quantitative textual analysis of the party's parliamentary speeches has shown that its political position is more left-leaning than that of its predecessor the Democratic Party.[58] Following its enlargement in 2020, the party has variously been described as liberal,[32][59] centrist,[60] or centre-left.[61][62] Within the CDP, as with its predecessor the Democratic Party of Japan (DPJ), there are conservative politicians,[c] as well as politicians from social-democratic backgrounds.[63][64][65]
A key characteristic of the CDP's policies, as its name suggests, is its respect for the Japan's postwar constitution which emphasizes democracy, human rights, and peace.[66] The term "constitutionalism" was a slogan used in protest movement against the Abe administration's the legislation for Peace and Security and constitutional revision from 2015 to 2017, and the party adopted the term as its name.[67] At launch in 2017, the CDP opposed the proposed revision of Article 9,[14][68][69] and in the 2017 general election, it campaigned on a traditional Japanese liberal message of firmly opposing the revision of the peace constitution.[44] The party supports the phasing out of nuclear energy in Japan,[70] and government investment in renewable energy.[71] The party does not support the legalization and maintenance of casinos.[72] The party supports "building a society that supports each other and makes full use of individuality and creativity".[73][74] In their 2017 political programme, the party expressed support for grassroots democracy and diplomatic pacifism.[75] It supports electoral reform.[76]
In 2019, the party pledged to support LGBT rights and the legalization of same-sex marriage in Japan,[77] and in March 2023, promoted a parliamentary bill for Japan to legally recognize such couplings.[78] It also supports increased gender equality.[79]
The party supported a freeze in the increase of the consumption tax as of 2017,[80][81] and supports a temporary consumption tax cut as of 2020, along with higher taxes on corporations and wealthy individuals.[25] In the run-up to the 2021 general election, party leader Edano stated his party's support for redistribution of wealth.[82] The 2021 election platform offered support for progressive taxation, a pledge for additional welfare payments for citizens on low incomes, and raising the capital gains tax rate to 25% by 2023.[83]
The CDP's 2024 platform supported raising the minimum wage, the abolition of tuition fees, free school meals, gender equality legislation and reform of laws regulating use of surnames following marriage in Japan.[84][85] The party also abandoned its previous policies of freezing or lowering the consumption tax rate.[86]
The CDP released a statement on its official website in August 2025 in which it stated that there was a need to recognize Palestine as an independent country.[87]
Leadership
Party Leader
As the highest-ranking official representing the party and overseeing its affairs, the Leader is elected by a vote of Diet members, prospective candidates, local assembly members, and party members/supporters. The term runs until the end of September three years after the year of election, starting from the day they take office.[88]
Acting Leader
The Acting Leader performs some of the duties of the Leader based on their instructions.
Deputy Leader
The Deputy Leader assists the Leader and carries out party affairs, based on the Leader's instructions, or upon the Secretary-general's request.
Secretary-general
The Secretary-General assists the Leader and oversees all aspects of party affairs execution; they may establish departments under their authority and appoint officers. They have an obligation to hear from regional organizations, local supporters, and party members.[88]
Policy Research Council Chair
They are responsible for the party's policies as well as for their investigation, research, and drafting.
Current leadership
As of 25 February 2026.[89] Only officials from the House of Councillors remain due to the formation of the Centrist Reform Alliance.
| Position | Name |
|---|---|
| President | Shunichi Mizuoka |
| Chairman in the House of Councillors | |
| Secretary-General | Masayo Tanabu |
| Chairman of the Standing Committee | Tadatomo Yoshida |
| Chairman of the Diet Affairs Committee | Yoshitaka Saitō |
| Chairman of the Election Strategy Committee | Shinji Morimoto |
| Chairman of the Policy Research Council | Eri Tokunaga |
List of leaders
| No. | Leader (birth–death) |
Constituency | Took office | Left office | Election results | |||
|---|---|---|---|---|---|---|---|---|
| Split from: Democratic Party (2016) (centre-left) | ||||||||
| 1 | Yukio Edano (b. 1964) |
.jpg) |
Rep for Saitama 5th | 3 October 2017 | 14 September 2020 | 2017
Unopposed | ||
| Merger of: Democratic Party For the People (centre-right; majority faction) & Some Independents Group | ||||||||
| 1 | Yukio Edano (b. 1964) |
|
Rep for Saitama 5th | 15 September 2020 | 12 November 2021 |
Yukio Edano – 107 Kenta Izumi – 42 | ||
| 2 | Kenta Izumi (b. 1974) |
.jpg) |
Rep for Kyoto 3rd | 30 November 2021 | 23 September 2024 |
Kenta Izumi – 205 Seiji Osaka – 128 | ||
| 3 | Yoshihiko Noda (b. 1957) |
_(cropped).jpg) |
Rep for Chiba 4th | 23 September 2024 | 19 January 2026 |
Yoshihiko Noda – 232 Yukio Edano – 180 | ||
| House of Representatives group merges into Centrist Reform Alliance | ||||||||
| 4 | Shunichi Mizuoka (b. 1956) |
 |
Councillor for National PR | 23 January 2026 | Incumbent | |||
Election results
House of Representatives
| Election | Leader | No. of candidates |
Seats | Position | Constituency votes | PR Block votes | Status | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| No. | ± | Share | No. | Share | No. | Share | |||||
| 2017 | Yukio Edano | 78 | 55 / 465 |
11.8% | 2nd | 4,852,097 | 8.75% | 11,084,890 | 19.88% | Opposition | |
| Merger of: Democratic Party For the People (centre-right; majority faction) & some Independents (2020) | |||||||||||
| 2021 | Yukio Edano | 240 | 96 / 465 |
20.6% | 2nd | 17,215,621 | 29.96% | 11,492,095 | 20.00% | Opposition | |
| 2024 | Yoshihiko Noda | 237 | 148 / 465 |
 52 |
31.8% |  2nd |
15,740,860 | 29.01% | 11,564,217 | 21.20% | Opposition |
| Merger with Komeito, forming the Centrist Reform Alliance (2026) | |||||||||||
House of Councillors
| Election | Leader | No. of candidates |
Seats | Position | Constituency votes | Party list votes | Status | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Won | ± | Total[e] | ± | No. | Share | No. | Share | ||||||
| 2019 | Yukio Edano | 42 | 17 / 124 |
32 / 245 |
2nd | 7,951,430 | 15.79% | 7,917,720 | 15.81% | Opposition | |||
| Merger of: Democratic Party For the People (centre-right; majority faction) & some Independents (2020) | |||||||||||||
| 2022 | Kenta Izumi | 51 | 17 / 125 |
39 / 248 |
2nd | 8,154,330 | 15.33% | 6,771,914 | 12.77% | Opposition | |||
| 2025 | Yoshihiko Noda | 51 | 22 / 125 |
5 |
38 / 248 |
 1 |
2nd | 9,119,656 | 15.42% | 7,397,456 | 12.50% | Opposition | |
See also
- Liberalism in Japan
- List of liberal parties
- Japan Socialist Party, the main opposition party in the "1955 System" against the LDP until the 1990s.
- Democratic Party of Japan
- List of major liberal parties considered centre-left
Notes
- Interim leader, as registered with the Minister for Internal Affairs and Communications.
- The "old CDP" was founded on 3 October 2017[1] as a split from the Democratic Party and dissolved on 14 September 2020,[2] while the current party was founded on 15 September 2020[3] as a merger of the old CDP, the majority of the Democratic Party For the People and some independent lawmakers.
- Most conservative factions within the CDP are moderate conservatives, but some CDP members belong to ultra-conservative Nippon Kaigi (ex: Hirofumi Ryu and Shū Watanabe).
- Held after the merger with the Democratic Party For the People.
- The Upper house is split in two classes, one elected every three years.