日本国とアメリカ合衆国との間の相互協力及び安全保障条約
As foreign minister, Okada was one of the chief participants in negotiations with the United States (US) over the relocation of Marine Corps Air Station Futenma on Okinawa. The Foreign Ministry under Okada also confirmed the existence of a long-rumored secret pact between Japan and US which had allowed the US military to carry nuclear weapons into Japanese territory in contravention of the Treaty of Mutual Cooperation and Security between the United States and Japan. The previous administration under the LDP had denied that such a pact existed.