Nagano had served as Navy Minister, but Japan's constitutional arrangement often made a service minister junior to the chief of staff. A prime minister who could not obtain a serving admiral or general for the cabinet could see the government collapse. A chief of staff could reinforce that leverage by ordering eligible officers not to serve. This imbalance allowed senior military leaders to influence policy far beyond ordinary departmental advice.
Chapter · 5:52-7:44
How the naval staff could overpower cabinet ministers
Japan's requirement for serving officers as service ministers gave senior staffs extraordinary leverage over civilian cabinets.