President Trump launched a global trade war when he imposed tariffs on steel and aluminum imports in early 2018. The President’s authority for imposing these tariffs came from an exceedingly vague statutory provision, section 232 of the Trade Expansion Act of 1962, which allows the executive branch to tax or block imports that “threaten to impair the national security” of the United States. That vague statute leads to a deeper constitutional question: Can Congress completely transfer its Article I powers over trade policy to the President?

On the one hand, the nondelegation doctrine stipulates that Congress cannot give away its legislative authority completely; it must include an “intelligible principle” to guide the executive branch in enforcing a statute. But on the other hand, the Supreme Court in United States v. Curtiss-Wright Export Corp. held that the nondelegation doctrine is far more lenient in the realm of foreign affairs than it is for domestic policy. One way of resolving this tension is to argue that the nondelegation doctrine applies to only certain areas of law and that it may not apply to foreign commerce. As of now, there is no clear alternative to this argument: Courts and scholars have instead cited Congress’s power to grant the President “broad authority” in foreign affairs, but they have not specified how broad this authority can be.

This Note argues that Congress can broadly delegate its authority to make trade policy, but that it cannot give this authority away entirely. The best way to make sense of the Supreme Court’s nondelegation jurisprudence is to account for the breadth of the delegation at issue: The Court seems willing to strike down a statute only when it gives away so much power that it essentially transfers an entire Article I authority to another branch of government. This Note shows that this conception of the nondelegation doctrine also extends to enumerated authorities that pertain to foreign affairs, like Congress’s authority to regulate foreign commerce. Constitutional text, purpose, practice, and precedent all show that Congress cannot completely transfer its foreign-commerce power to the President.