Why civil war is the likeliest outcome

Hirohito was expected to reign without visibly ruling. Publicly elevating Yonai through an explicit imperial act could alarm factions that accepted the throne only while they retained room to claim its authority for themselves. Hirohito had also seen his father's effort to modernize and liberalize Japan more rapidly end in failure, after which he assumed governing responsibilities before formally succeeding. An emperor exercising unmistakable power threatened the tacit bargain that had kept rival claimants to imperial legitimacy inside one regime, making civil war the likeliest outcome.