Chapter 2 has demonstrated that it is possible to construct a structural logic of social protection by identifying the configuration of veto players and the specific institutional constraints on their preferences (that is, district magnitude and the relative importance of the personal vote). This chapter applies my structural logic approach to explain welfare state development in Japan. In contrast to the more comparative orientation of the previous chapter, this chapter claims that my structural logic approach can explain two sets of variations in policy outcomes within the same country: (i) cross-policy variations during the same period; and (ii) historical variations. To put it simply, cross-policy variations can be understood as a reflection of the relative power of different actors and their preferences. In other words, programs sought by influential actors have a better chance of being adopted, whereas programs they oppose have a worse chance. My structural logic explains cross-policy variations by predicting which actors have the most power in a specific institutional context. Granted this approach, it follows that policy shifts in social protection happen when (i) the veto player configuration changes; and/or (ii) veto players' preferences change. Historical shifts in welfare politics can be understood in terms of the shifts in the power distribution within a polity and the changes in the preferences of the veto players.

This chapter proceeds in four sections. Section 1 chronicles historical shifts in the government type, district magnitude, and the relative importance of the personal vote that occurred in postwar Japan.