Recent efforts to constrain the administrative state have attracted widespread attention. Yet the conversation has largely overlooked the substantial international elements of agency power, which often serve as power multipliers. Agencies frequently invoke international factors as reasons to regulate, not to regulate, or to regulate in a certain way. The factors include binding U.S. international law obligations like Article II treaties, executive agreements, and customary international law, but also more malleable nonbinding sources like regulatory soft law, political commitments and foreign policy, and national security interests.

This Article analyzes the complex framework that structures the international elements of agency power, exposes its incoherence with related foreign relations law frameworks, and considers the impact of the Supreme Court’s broader reassessment of key administrative law doctrines, most recently in West Virginia v. EPA.

I argue that extant administrative law allows broad incorporation of international factors in domestic regulation even absent specific congressional authorization. This principle, which I call the basic rule of agency discretion, creates a major loophole at the heart of foreign relations law, which now generally requires explicit congressional authorization for international law to become enforceable in domestic law. I then argue that although West Virginia v. EPA’s new major questions doctrine could resolve this tension in favor of the foreign relations law rule, it is more likely to exacerbate it because the doctrine may still allow a broad foreign relations exception to new limits on delegation.

How might these developments impact agency freedom to engage with the world? The anti-regulatory turn of the last few years could increase regulatory isolationism dramatically through new limits on agency discretion. But that outcome is not a certainty. I sketch three possible scenarios for how the new major questions doctrine might operate in relation to international regulatory factors: an absolutist approach, an exceptionalist approach, and a stratified approach. I argue that an absolutist approach is unsustainable. I then identify advantages in both the exceptionalist and stratified approach for those seeking to preserve as much of the “old”, permissive, administrative law framework for agency consideration of international factors as possible.