One of the important questions in the interpretation of Rawls’s philosophy is the connection between the two problems he wrote about throughout his life – justice and legitimacy. In this paper, I take the difference principle as a special feature of Rawls’s theory of justice, while I take the idea of the public reason as a special aspect of his theory of legitimacy, and I try to show that both aspects are connected, that is, that we should not see them as two separate projects. I am trying to show that we should formulate the justification of the difference principle as a justification of a particular socio-economic arrangement rather than as an abstract principle, one that is better than other legitimate arrangements. For Rawls, property-owning democracy and liberal socialism are socio-economic arrangements that realize the difference principle. The main difference between the two systems is that in the first one, private ownership of the means of production is allowed, but it is widely dispersed. In this paper, I try to show how such a system can be publicly justified. The justification that we need to use is precisely the one that Rawls formulates through the idea of the public mind, by referring to the political values contained in our public political culture.