After the Shimonoseki War, the Choshu clan maintained its opinion on the expulsion of foreigners, based on the idea of Sonno; however, when Emperor Komei permitted the Treaty of Amity and Commerce between the United States and Japan in 1865, Sonno and the expulsion of foreigners could no longer be connected, and those advocating the expulsion of foreigners lost their power.
長州藩は下関戦争の後尊皇論を基盤に藩論は攘夷で維持していたが、1865年、日米修好通商条約に孝明天皇が勅許を出したことにより尊皇と攘夷は結びつかなくなり、攘夷の力が失われた。