Reconciling diversity and social cohesion is a common concern in constitutional studies, one that has often been resolved by resorting to federal forms of government. Economic inequalities can also prompt the choice of federalism. The goal of this presentation is to offer a preliminary theorization of economic asymmetries in public law and identify how federal constitutions can balance their unifying role while curbing economic inequalities. By embracing a theoretical and normative approach, the presentation explores how certain federal-based mechanisms running both horizontally and vertically (fiscal federalism being an example) could be better employed to help reconcile socio-economic differences. I propose a two-prong argument: first, I recommend taking economic inequalities more seriously. Next, I claim that the principle of (federal) solidarity represents the legal foundation on which richer or economically successful regions can be required to help poorer regions.