[24] On 22 March, the DPJ announced that 4 sitting Representatives from Vision of Reform would join the party at its launch.

[26] The party platform committed to protecting the existing pacifist Japanese constitution, and stating opposition to the "Abenomics" policies of Prime Minister Shinzō Abe.

[32] 33 candidates contested the single- and multi-member districts and 22 were in the party's list for the 48-seat national proportional representation block.

The party suffered a considerable defeat at the hands of the ruling coalition, losing 13 seats overall.

Five of the 15 endorsed independents were also elected, including two that claimed seats formerly held by retiring Democratic Party members.

[33] Following the loss, Okada announced he would not seek re-election as leader at the party's annual meeting in September.

[35] The election for a new leader to replace Renhō took place on 1 September, and campaigning began on 21 August.

[40][41] On 28 September 2017, Maehara announced that the party had abandoned plans to contest the 2017 general election scheduled for 22 October.

[44] On 2 October 2017, DP deputy president Yukio Edano announced the formation of the Constitutional Democratic Party of Japan (CDP) for liberals and left-leaning members of the DP whom Koike had rejected for running as Party of Hope candidates.

[47][48] On 31 October 2017, member of the House of Councillors Kohei Otsuka was chosen as the leader of the Democratic Party to succeed Maehara.

Most of these joined the formation of the "Group of Independents" (Mushozoku no kai) House of Representatives caucus led by Katsuya Okada in October 2017.