Even among supporters of the welfare state there are several different theoretical reconstructions of the normative commitments that are taken to underlie it, all of which are in tension with one another. The three normative purposes most commonly cited are equality, community, and efficiency. These give rise to a corresponding set of models, which I refer to as the egalitarian, communitarian, and public-economic models of the welfare state. The objective of this chapter is to show that the public-economic model of the welfare state, though the least popular among political philosophers, is actually the most plausible. Not only does it provide a superior account of the existing configuration of welfare-state activities, but it alone is able to explain why, in all Western democracies, state spending rose almost continuously over the course of the 20th century.