This article provides an original analysis about the unbalance present in the World Trade Organization from its very origin, taking the Agreement on Agriculture as an explicit example of it. The reflection is done through a case study on the distorting domestic subsidies in agriculture allowed by that Organization to the United States and Brazil, using as a reference of justice the toolbox provided by John Rawls' "Justice as Fairness" theory. The article explores alternative criteria for the establishment of multilateral commitments, based on Rawls' concepts. The reflection serves as a parameter or a starting point for thinking the reform of the multilateral trade system and the establishment of possible new commitments within it.