The Two Faces of the Single Tax Principle

Abstract

This short paper, prepared for a symposium, “Reconsidering the Tax Treaty,” to be held at Brooklyn Law School on October 23, 2015, examines the “single tax principle,” arguably underlying bilateral tax treaties, in connection with evaluating the treaties’ future role in the development of international tax law and policy. It distinguishes between “upside” departures from the single tax principle, which occur when the same dollar of income is taxed more than once, and “downside” departures, which occur when it is not taxed at all.The paper argues that a focus on barring upside departures from the single tax principle can be quite misguided. While over-taxing cross-border activity, relative to that occurring in one country, may be undesirable, this should not stand in the way of letting residence countries tax foreign source income at a reduced rate, in lieu of wholly offsetting source country taxes via foreign tax credits. As for barring downside departures from the single tax principle, such as by addressing stateless income, while this often is desirable from a given country’s unilateral national welfare standpoint (and is even more clearly worth pursuing multilaterally), the issues raised are more complicated than adherence to the single tax principle might appear to suggest.