In this paper, I present the suggestion that a suitable theory of “justice as fairness” could offer a consistent path for solving many issues related to the actual crisis of the classical liberal model of economy and democracy, by substituting the abstract “equality” principle, with the concrete “equity” one in the notion of justice. After a short discussion of some main characters of the present worldwide crisis of the classical liberal model, I present two main theories of justice as fairness. John Rawls’ theory in political philosophy that emphasizes how really equitable judgements must overcome the equalitarianism of the Classical Liberalism, by considering the real possibilities of individuals and groups of accessing and enjoying commodities and utilities, as well as, the “basic liberties” defining the citizen equal dignity in the Modern State. Rawls propose, therefore, a notion of fairness compliant with the Kantian normativism, and a notion of fair distributive justice based on the ethical principle of the maximin, as a criterion for judging the righteousness of the State Institutions. The other theory of justice as fairness I discuss in this paper is an evolution of Rawls’ in the direction of the development of a “comparative distributive justice”, without any normativism. This theory is developed in the context of the newborn discipline of the “social choice theory”, formalizing social decision processes, with applications in economic, social, and political sciences. What characterizes Sen’s theory is its original synthesis between the Aristotelian notion of fairness, based on the “personal flourishing”, and Adam Smith’s ethical principle of the “extended sympathy”, by which making comparable different approaches to pursue the personal flourishing, i.e., for achieving “valued and valuable ways of being and of doing”, compliant with, and respectful of, different value systems.