The Normative Case for a Global Minimum Tax on Ultra-High-Net-Worth Individuals

Gabriel Zucman presents his proposal for a global minimum tax on billionaires as one that citizens must debate. They have to weigh the benefits and costs and ultimately decide whether to adopt it. In this article, we aim to contribute to this debate by discussing relevant insights from economic ethics and political philosophy. Our main claim is that the normative case for Zucman’s proposal is very strong because it is overdetermined: there are multiple reasons that are, if each is taken individually, sufficient to justify the proposal. Such a global minimum tax would help address unmet urgent needs, promote social cohesion and relational equality, contribute to climate fairness and ecological transitions, and improve the functioning of democracies. It would also bring the tax system closer in line with the ability-to-pay principle and help reduce undeserved wealth inequality. All these normative considerations combined show that citizens have good reasons to adopt the proposal. If anything, these considerations imply that citizens should, ultimately, aim for an ambitious variant of the proposal.