Publication Date

2026

Journal

Washington University Law Review

Abstract

The U.S. Constitution’s Treaty Clause, which requires Senate approval by a two-thirds vote for treaties, has significantly influenced the development of international tax law. This Article examines the implications of Senate supermajority requirements on bilateral and multilateral tax treaties and agreements, alternative instruments, relevant international tax standards, and global tax governance.

Historically, tax treaties have been approved exclusively as Article II treaties requiring Senate approval. The difficulty of entering into treaties with the United States has influenced the instrument choice and design of U.S. and international tax standards. To address this challenge, several U.S. and international tax reforms have employed “treaty avoidance” strategies, including coordinated unilateralism and reliance on executive agreements. While these approaches may circumvent the need for Senate approval, they may result in second-best solutions, violate existing treaty obligations, or raise additional concerns, such as extraterritoriality and lack of legitimacy.

This Article examines the increasing use of executive agreements. Since 2011, while approval of U.S. bilateral tax treaties has nearly ceased, there has been a significant increase in executive agreements, primarily for information exchange for tax purposes. Furthermore, the use of congressional-executive agreements in international taxation may continue to expand, drawing on precedents from international trade law and other legal fields. For example, the Biden administration considered implementing the Pillar One reform through a congressional-executive agreement—an approach that may be followed in future international tax reforms. In addition, pending legislation would provide statutory treaty-like tax benefits and approve a tax treaty with Taiwan as a congressional-executive agreement. These developments represent an erosion of the tradition of approving tax treaties as Article II treaties and a shift toward greater reliance on alternatives, such as the use of executive agreements.

Nonetheless, it remains uncertain to what extent executive agreements will replace Article II treaties in the international tax domain. Failure to revisit the instrument choice in international taxation may compromise U.S. interests and global cooperation as the U.S. treaty ratification process makes it unlikely that the United States will participate in any future convention for global tax governance. If other countries enhance their international tax cooperation without U.S. participation, this may lead to further bifurcation of the international tax governance system. This would raise the risk of eroding U.S. influence in global tax matters, potentially leading to international standards less favorable to U.S. stakeholders. A bifurcated system without U.S. participation may result in standards inferior to those that could have been achieved with U.S. participation.

Volume

103

First Page

2081

Last Page

2117

Publisher

Washington University in St. Louis School of Law

Disciplines

Constitutional Law | International Law | International Trade Law | Law | Tax Law

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