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 a member of the US House of Representatives, Donald Rumsfeld was among the first participant in JCIE's US-Japan Parliamentary Exchange, beginning a long professional relationship between Yamamoto and Rumsfeld. In 1975, Yamamoto organized a meeting at the White House between Rumsfeld, who was the White House Chief of Staff for President Gerald Ford, and the Vice Chairman of the now defunct Japanese Socialist Party, Saburō Eda. Yamamoto made the meeting possible, despite Socialist Party's opposition to the Treaty of Mutual Cooperation and Security between the United States and Japan. As the first meeting between the Socialists and US government officials in 23 years, the visit opened the way for a new engagement with Japan’s main opposition party.