But his reforms suffered setbacks, such as a conflict between bakufu and Imperial Court over Imperial permission to the treaty concluded with US, a conflict within bakufu over the successor to the sickly shogun between "Hitotsubashi group" (the group that recommended Yoshinobu TOKUGAWA [later, the 15th Shogun]) and "Nanki group" (the group that recommended Iemochi TOKUGAWA [later, the 14th Shogun]), and Naosuke Ii's assumption of "Tairo" (Chief Minister of bakufu) - Naosuke Ii was at the top of "fudai daimyo" and was against the participation of "tozama daimyo" and "gosanke" in bakufu politics.
だが条約勅許をめぐる朝廷との対立や、病弱な将軍の後継を巡る一橋派（徳川慶喜・後の15代を推す勢力）と南紀派（徳川家茂・後の14代を推す勢力）との対立、また外様や御三家の幕政介入に反撥した譜代大名の筆頭井伊直弼が大老に就任したことにより改革は挫折した。