In 2014, at the age of 75, Hosokawa was approached by the DPJ to run in the Tokyo gubernatorial election.
Although Hosokawa initially turned down their request, former Prime Minister Junichiro Koizumi encouraged him to run for the primary purpose of gathering public opposition to Prime Minister Shinzō Abe's pro-nuclear policies, and Hosokawa again considered running for the office.
This was initially perceived as a blow to Yōichi Masuzoe, the LDP-supported candidate who was also supported by elements within the DPJ and who had previously been considered the lone front-runner in the race; the race between Masuzoe and Hosokawa became widely dubbed as a "proxy contest" between Abe and Koizumi.

Hosokawa announced his candidacy alongside Koizumi on January 14.
His campaign was supported by several key members of his 1993-94 coalition: Banri Kaieda and Ichirō Ozawa, who had since become the heads of the Democratic Party of Japan and People's Life Party respectively, threw their support behind Hosokawa, while Shusei Tanaka and Yoriko Madoka were enlisted as his policy advisors.

During his campaign, Hosokawa criticized the Abe government's nuclear policy, stating: "Tokyo is shoving nuclear power plants and nuclear waste to other regions, while enjoying the convenience (of electricity) as a big consumer."
He also criticized Abe's foreign policy in the run-up to the 2020 Summer Olympics in Tokyo, questioning "whether pugnacious diplomacy will help the festival of peace to be held smoothly."

Hosokawa failed to gain momentum and trailed behind Masuzoe in the polls through the final week of the campaign, with only a 30–40% support rating within the DPJ and PLP and particularly low support among women.
Masuzoe was declared the winner in exit polls shortly after voting ended on February 9, but Hosokawa vowed to continue anti-nuclear advocacy.
In 2014, at the age of 75, Hosokawa was approached by the DPJ to run in the Tokyo gubernatorial election. Although Hosokawa initially turned down their request, former Prime Minister Junichiro Koizumi encouraged him to run for the primary purpose of gathering public opposition to Prime Minister Shinzō Abe's pro-nuclear policies, and Hosokawa again considered running for the office. This was initially perceived as a blow to Yōichi Masuzoe, the LDP-supported candidate who was also supported by elements within the DPJ and who had previously been considered the lone front-runner in the race; the race between Masuzoe and Hosokawa became widely dubbed as a "proxy contest" between Abe and Koizumi.
Hosokawa announced his candidacy alongside Koizumi on January 14. His campaign was supported by several key members of his 1993-94 coalition: Banri Kaieda and Ichirō Ozawa, who had since become the heads of the Democratic Party of Japan and People's Life Party respectively, threw their support behind Hosokawa, while Shusei Tanaka and Yoriko Madoka were enlisted as his policy advisors.
During his campaign, Hosokawa criticized the Abe government's nuclear policy, stating: "Tokyo is shoving nuclear power plants and nuclear waste to other regions, while enjoying the convenience (of electricity) as a big consumer." He also criticized Abe's foreign policy in the run-up to the 2020 Summer Olympics in Tokyo, questioning "whether pugnacious diplomacy will help the festival of peace to be held smoothly."
Hosokawa failed to gain momentum and trailed behind Masuzoe in the polls through the final week of the campaign, with only a 30–40% support rating within the DPJ and PLP and particularly low support among women. Masuzoe was declared the winner in exit polls shortly after voting ended on February 9, but Hosokawa vowed to continue anti-nuclear advocacy.
Morihiro Hosokawa