After returning from the trip to the western countries, SUGI made efforts with Kaoru INOUE for peace negotiations of the Shimonoseki War, while he opposed to military clashes against the conservative parties, during the domestic conflict of the Genji period.
帰国後、下関戦争では井上馨とともに和議に尽くし、元治の内乱では高杉晋作を支持しつつも、保守派との軍事衝突には最後まで反対した。