As Julian Ku notes on Opinio Juris, the U.S. Court of Appeals for the D.C. Circuit's opinion in NRDC v. EPA has potentially important implications for the domestic implementation of international treaty commitments. Specifically, the D.C. Circuit panel held that the post-ratification consensus agreements reached by parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (of which the United States is one), are not "law" enforceable in federal courts.

Methyl bromide, a naturally occurring gas that is also used as a fumigant in crop and produce production, is one of the substances to be phased out under the Montreal Protocol. The U.S. ratified the protocol and subsequently adopted implementing legislation as part of the 1990 Amendments to the Clean Air Act. In 2004, the EPA issued a rule identifying the "critical uses" of methyl bromide that are exempt from the general ban on production and consumption. NRDC believed that the EPA's rule was too permissive, and violated the Montreal Protocol, so it sued in federal court.

The first time around, NRDC lost on standing grounds (more on that in another post). On rehearing, however, the D.C. Circuit found NRDC had standing, but rejected NRDC's claim that the EPA's action violated U.S. law. Even if the EPA's methyl bromide crucial use exemptions were broader than allowed under post-ratification decisions made by the parties to the Montreal Protocol, the court held in an opinion by Judge Randolph, such decisions "are not 'law' within the meaning of the Clean Air Act and are not enforceable in federal court."

If the "decisions" are "law" -- enforceable in federal court like statutes or legislative rules -- then Congress either has delegated lawmaking authority to an international body or authorized amendments to a treaty without presidential signature or Senate ratification, in violation of Article II of the Constitution. . . .

A holding that the Parties' post-ratification side agreements were "law" would raise serious constitutional questions in light of the nondelegation doctrine, numerous constitutional procedural requirements for making law, and the separation of powers. We need not confront the "serious likelihood that the statute will be held unconstitutional." . . . It is far more plausible to interpret the Clean Air Act and Montreal Protocol as creating an ongoing international political commitment rather than a delegation of lawmaking authority to annual meetings of the Parties. . . .

Our holding in this case in no way diminishes the power of the Executive to enter into international agreements that constrain its own behavior within the confines of statutory and treaty law. The Executive has the power to implement ongoing collective endeavors with other countries. . . . Without congressional action, however, side agreements reached after a treaty has been ratified are not the law of the land; they are enforceable not through the federal courts, but through international negotiations.

Judge Edwards also wrote a concurring opinion addressing some of the implications of the decision for the enforcement of other international agreements, arguing that the opinion should not be read to preclude the enforcement of post-ratification decisions under other agreements in other contexts:

we do not decide here whether, once the United States undertakes a substantive obligation in a treaty, and at the same time undertakes to abide by the result of a specified dispute resolution process before an international tribunal, it is bound by the judgments of the tribunal no less than it is by the treaty that is the source of the substantive obligation. That question is not before us.

Although the decision does not directly hold that Congress cannot delegate policy authroity to international orgnaizations, it highlights the constitutional questions that such a delegation would raise. It is one thing to delegate quasi-legislative authority to a domestic agency, whether in the executive branch or an "independent" agency. It is quite another to delegate such authority to an international entity that is not bound by U.S. law or responsive to U.S. constituencies.