Deference in Treaty Interpretation after Loper Bright v. Raimondo

For nearly a century, the Supreme Court has exercised what this Article calls "treaty deference." This is a form of judicial deference that extends not only to the Executive's conduct of national security and foreign relations generally but also more specifically to its interpretation of Article II treaties. The Court's reasons for treaty deference have varied. Some are unique to U.S. national security law and foreign relations law and thus support a view of both as grounded in "exceptionalism"-their substantial differences from law with little impact on national defense or foreign affairs. In contrast, some of the Court's reasons for treaty deference are not unique to foreign relations law and are similar to the bases once advanced in support of Chevron deference in administrative law. These reasons support the "normalization" thesis-that the distinctive form of federalism and separation of powers in the foreign affairs context has waned and will continue to decline. This Article argues for the reexamination of treaty deference in light of Loper Bright v. Raimondo, which in 2024 ushered in the post-Chevron era. This reexamination can lead to two very different outcomes: the first is one that brings the demise of treaty deference and a major step toward the normalization of law related to national security and foreign affairs. This Article rejects this outcome in favor of a second one by which treaty deference persists and comes to rest solely on reasons drawn from foreign relations exceptionalism.