Amidst the release of Why You Can't Be Prime Minister [ja], a documentary focused on Ogawa's political life, he gained popularity and name recognition across the country.

[5] In 1999, he was assigned to the London office of the Council of Local Authorities for International Relations, an external organization of the Ministry of Home Affairs.

[12] As Ogawa began to doubt working as a bureaucrat,[12] he met Asahi Shimbun reporter Hiroshi Samejima [ja].

At the time, Samejima was covering Naoto Kan, who was Secretary-General of the Democratic Party of Japan, and Deputy Secretary General Seiji Maehara.

When the 2010 House of Councillors began, the LDP announced it would field Yoshihiko Isozaki, an employee of All Nippon Airways, for the Kagawa at-large district.

[24] In the September 2012 DPJ leadership election [ja], he attempted to convince Goshi Hosono, who was serving as Minister of the Environment, to run for president.

Despite Hosono initially agreeing, he was talked out of running by senior party members, and eventually gave up on gathering endorsements.

In February 2014, the DPJ Kagawa prefectural federation held a regular convention, and Ogawa was elected as the new representative, succeeding Yuichiro Tamaki.

In April, they began preparations to make Tanabe Kenichi the unified candidate, who was a prefectural standing committee member endorsed by the Japanese Communist Party.

On July 11, Ogawa apologized for not fielding an independent candidate and announced his intention to resign as prefecture party head.

[37] The following day, Maehara holed up in a hotel room with Ogawa and Atsushi Oshima, who acted as his campaign manager in the leadership election.

[38] On 5 September, the Democratic Party held a general meeting of both houses of parliament and approved the executive personnel changes proposed by Maehara.

[39] On 26 September 2017, Governor of Tokyo Yuriko Koike, who had by this time formed Kibō no Tō, met with Democratic Party chairman Seiji Maehara and RENGO Japan President Rikio Kozu in secret.

They agreed to merge the Democratic Party together with Kibo no To for the upcoming general election, a day after Abe dissolved the Diet.

[43] A day later, Ogawa responded to an interview by the Mainichi Shimbun, saying that "I think its a just cause in confronting the (LDP-Komeito) government," and expressed positive feelings towards the merger.

[52][53] In the nine point policy collection, she resolved to "Advance the debate on constitutional amendment, including Article 9", and "build a diplomatic and security system based on realism.

[58] On 27 October, Kibō no Tō held a general meeting of representatives from both chambers and opted to vote for party co-chair Shu Wantanabe for Prime Minister.

[59] Ogawa openly advocated for instead voting for Yukio Edano of the Constitutional Democratic Party of Japan in front of Yuriko Koike at the meeting.

[5] In the party's executive changes following the 2017 leadership election, he was appointed Chairman of the Social Security System Research Council.

Ogawa held a press conference at the prefectural office and announced he would not join the new party, instead remaining independent for the time being.

[61] On 9 September, he announced his intention to sit with the CDP's parliamentary group in the House of Representatives as an independent, and joined the following day.

[66] On 24 August, Tetsuro Fukuyama, who was serving as Secretary-General of the Constitutional Democratic Party, and Hirofumi Hirano, who was serving as Secretary-General of the Democratic Party For the People, met with Kōichirō Genba, who was a member of the technical Group of Independents, and Ogawa, who sat with a group of technical independents led by Katsuya Okada.

[69] In early August, together with Kishirō Nakamura, he toured stone and soy sauce brewing industries, long-standing businesses which are considered close to the LDP.

A social media team was also formed, mostly consisting of photographers and designers who support Ogawa, and began to assist in making his Instagram and YouTube posts.

[79] On 10 October, Tamaki posted on Twitter that "I have nothing to do with fielding a candidate for Nippon Ishin no Kai in the Kagawa 1st district, and I have no intention of being involved in it in the future.

"[79][80] On 12 October, the Shikoku Shimbun published an article titled "Ishin newcomer forced to give up running: CDP's Ogawa in Kagawa 1st district.

"[79] On 15 October, Machikawa responded to an interview with the Shikoku Shimbun, revealing that a LDP prefectural assembly member had encouraged them to run in the Kagawa 3rd district.

The Shikoku Shimbun analyzed the early stages of the election based on a telephone poll conducted by Kyodo News on the 19th and 20th, as well as information obtained through interviews.

[95] During the leadership election, Ogawa began holding "Open-Air Dialogue Meetings" in front of the Yurakucho ITOSIA building in Chiyoda, Tokyo.

The group was started by Ogawa, Tomoko Abe, Shūji Inatomi, Ichirō Ozawa, Sayuri Kamata, Makiko Kikuta, Yoshio Tezuka, Kazuhiro Haraguchi, Kenko Matsuki, Michiyoshi Yunoki, and Shunji Yuhara.