On 28 September 2017, Democratic Party leaderSeiji Maehara announced that the party had abandoned plans to contest the 2017 general election, with the party's sitting representatives contesting the election as candidates for the Kibō no Tō recently founded by former Tokyo governor Yuriko Koike, or as independents. On 23 October 2017, after the election, Maehara resigned as party president, with the Constitutional Democratic Party of Japan having replaced the DP as the largest opposition party in the House of Representatives, while the existing DP caucus continued to exist in the House of Councillors. In January 2018, the DP and the Kibō no Tō agreed to form a joint parliamentary group in both houses of the Diet, although days later the negotiations broke down. On 9 April 2018, it was announced that talks were ongoing to merge the two parties into a new opposition force. On 24 April 2018, at a joint press conference the leadership of the DP and the Kibō no Tō announced that both parties had agreed to merge in May 2018 as the National Democratic Party. The DP and Kibō no Tō merged to form the DPFP on 7 May 2018. 62 members of the predecessor parties joined the DPFP at its formation. DP leader Kōhei Ōtsuka and Kibō leader Yūichirō Tamaki became the interim co-leaders of the new party. The party held a leadership election in September 2018 to choose a permanent leader. Interim co-leader Tamaki was elected as the permanent leader of the party. In April 2019, the Liberal Party merged into the Democratic Party for the People.
Ideology
A self-proclaimed "reformist centrist" party, it enumerated freedom, symbiosis and responsibility for the future in its basic philosophy and self-proclaimed the establishment of a "Reformist-Centrist Party" based on these philosophies. Otsuka said that the term "Reformist-Centrist Party" describes attitude and spirit of DPFP that thoroughly adheres to a democratic approach to realistically reform/solve various issues. However, the party is viewed as having a strong "reformist conservative" tendency because the split of the DP has drained liberals to the CDP.
