When reading contemporary theories of distributive justice, one could easily get the impression that questions of fiscal design are normatively speaking merely instrumental for realizing the distributive ideal. Once the overall conception of justice is settled upon, questions of how the state should arrange its institutions and policies are settled if they effectively and efficiently promote the preferred distribution. I argue that such pure instrumentalism is mistaken in the context of fiscal policy. As a result, there is nothing problematic or morally arbitrary about accepting domain-specific principles of fiscal justice.