Shinjiro Koizumi

Shinjiro Koizumi is a Liberal Democratic Party member of the Japanese House of Representatives, representing Kanagawa Prefecture's 11th district since 2009. He served as Minister of the Environment in the cabinet of Prime Minister Yoshihide Suga from September 2019 to October 2021. His portfolio included climate-change policy, decommissioning planning for the Fukushima Daiichi nuclear facility, and the management of disposal arrangements for tritiated water from the same facility.

He is the son of former Prime Minister Junichiro Koizumi. Before entering electoral politics he worked as a researcher at the Center for Strategic and International Studies in Washington, DC.

At the inaugural meeting of the Parliamentary League for Unraveling Unidentified Anomalous Phenomena from a National Security Perspective on 6 June 2024, he was named Secretary General. His procedural role is to manage the League's working sessions, coordinate cross-party communications, and oversee preparation of the League's formal proposals to the executive branch.

Koizumi's public statements on UAP have been procedural confirmations of the League's activities at press conferences alongside Chair Yasukazu Hamada and other League members. He has not, on the public record, characterised the substance of the UAP question outside the operational and national-security framing the League has adopted.

The League has met formally four times since June 2024 and has delivered two written proposals to the executive branch: the 16 May 2025 proposal to Defense Minister Gen Nakatani calling for a dedicated UAP division within the Ministry of Defense, and the 30 March 2026 proposal calling for a coordinating UAP office under the Deputy Chief Cabinet Secretary for Crisis Management. The 30 March 2026 proposal was formally submitted to the executive branch on 16 May 2026 with Diet member Gen Nakatani among the signatories.