In this paper I present and analyze the communitarian theory of Michael Walzer regarding the difference between the spheres of social justice. From this theoretical perspective, Walzer argues that the distribution of citizenship should be open to those categories of foreigners, such as refugees or guest workers that inhabit the territory of a political community. I underline the fact that this theory of “potential citizenship” is not compatible with the communitarian theory mentioned above. In the final section of the paper I suggest that a solution for maintaining the potential citizenship thesis is to offer a weaker reading of the communitarian thesis, according to which the acceptance of some principles of distribution should be based on the fact that a justification would be available for the belief that those principles are likely to be the right ones.