A stronger treaty rewards cooperative Japanese factions

What effect did factions within Japan have on the postwar situation?

Japanese factional politics historically helped drive Britain away. A stronger Four-Power guarantee could give supporters of naval compromise a domestic argument for accepting shipbuilding limits.

Domestic politics and international bargaining reinforce one another in this scenario. Japanese leaders accepting limits on shipbuilding could point to a defensive arrangement binding several great powers as compensation. That gives pro-alliance factions a concrete achievement to use against rivals who equate national status with independent military expansion. Security guarantees could therefore change which Japanese political program appears to deliver prestige and safety.