The scope of the treaty power

Monday's Supreme Court decision in Bond v. United States, 2014 DJDAR 6919, largely avoided the big constitutional issue that was the original focus of the case: the scope of the treaty power. But the ruling still has some important implications for the future. All nine justices expressed serious qualms about the argument that treaties can authorize Congress to legislate beyond the scope of its other enumerated powers. The need to enforce constraints on the treaty power is more than just an abstract legal question in an age where treaties cover an enormous range of issues.

Microbiologist Carol Anne Bond found out that a close friend of hers had been sleeping with Bond's husband and had become pregnant by him. Seeking revenge on the other woman, Bond tried to harm her by coating her mailbox and door knob with toxic chemicals. However strange, this type of crime is normally the province of local law enforcement. Few predicted that this love triangle would ultimately result in two Supreme Court decisions. But federal prosecutors decided that their state counterparts were not going after Bond aggressively enough. They therefore prosecuted her for violating 18 U.S.C. Section 229, the federal law implementing the Chemical Weapons Convention, which bans the use and possession of chemical weapons.

Section 229 bans the use and possession of all "chemical weapons," broadly defining that category to include any "toxic chemical and its precursors, except where intended for a purpose not prohibited under this chapter as long as the type and quantity is consistent with such a purpose." The excepted purposes are "[a]ny peaceful purpose related to an industrial, agricultural, research, medical, or pharmaceutical activity or other activity." Bond argued that her prosecution went beyond the limits of congressional power, as restricted by the 10th Amendment. The case reached the Supreme Court in 2011, at which time the justices unanimously ruled that individuals, as well as state governments, could raise federalism issues in court. As the court explained, "[f]ederalism secures the freedom of the individual" as well as the autonomy of state governments.

The first Bond decision left open the issue many people expected to be addressed in Monday's ruling: whether the federal government can use treaties to get around federalism constraints on the scope of congressional power. The treaty clause of the U.S. Constitution gives the president and the Senate the power to make and ratify treaties. Congress often enacts further legislation to implement them. Even if Section 229 might otherwise be unconstitutional, perhaps it is permissible because it implements a treaty. Missouri v. Holland, a 1920 decision, suggested that the treaty power can indeed be used to reach issues otherwise outside the scope of congressional authority. But that unsupported passage in Holland may not have been necessary to resolve that case, and has come under severe criticism by legal scholars, most notably Georgetown law professor Nicholas Rosenkranz.

Ultimately, the Supreme Court avoided the big constitutional issue at stake in the case. Despite the extremely broad language of Section 229, six justices ruled that it does not cover Bond's crime. But the majority opinion still has at least some implications for the treaty power question. In order to interpret Section 229 to exclude Bond's conduct, Chief Justice John Roberts applied the rule against construing federal laws in a way that upsets "the usual constitutional balance of federal and state powers" unless the law does so very clearly. In this case, the court interpreted the law narrowly so as to avoid federal intrusion into "local" criminal conduct. But the prosecution of Bond would not upset "usual constitutional balance" between the states and the federal government if the latter has an unlimited power to sign and implement treaties regardless of their subject matter. In that event, a treaty covering "local" conduct would be just business as usual. Thus, the majority opinion strongly suggests that there are serious doubts about whether the treaty power can reach local crimes like those committed by Bond.

Justice Antonin Scalia's concurring opinion (joined on this point by Justices Clarence Thomas and Samuel Alito) correctly rejects the majority's narrow interpretation of Section 229. As Scalia emphasizes, Section 229 seems both clear and broad, forbidding all use and possession of "toxic substances" unless for a "peaceful purpose." Bond obviously used and possessed toxic substances. Equally obviously, the use was not peaceful.

Scalia, joined by Thomas, also concludes that the treaty power does not give Congress the authority to enact implementing statutes that go beyond the scope of Congress' other enumerated powers under Article I. In a separate concurring opinion, Thomas, joined by Scalia and Alito, argues that Section 229 is unconstitutional because the treaty power only extends to treaties addressing "matters of international intercourse," but does not cover "matters of purely domestic regulation," such as Bond's conduct.

Scalia and Thomas are right to conclude that Section 229 is unconstitutional. But there are some flaws in their reasoning. Scalia's argument implies that the federal government has the power to sign treaties on a broader range of issues than Congress can legislate to implement. As he puts it, the "power to help the President make treaties is not a power to implement treaties already made." The latter, he reasons, does not extend to treaties outside the scope of Congress' enumerated powers.

But a constitutionally valid treaty can only cover subjects that are within scope of preexisting federal power to begin with. As Federalist 64 puts it, "a treaty is only another name for a bargain" - a contract between governments. A valid contract between individuals can only cover such issues as those individuals have a preexisting right to decide. A and B cannot legally sign a contract disposing of the property of C. Similarly, a treaty between national governments can only address issues within the scope of those governments' powers. Article VI of the Constitution makes treaties "the supreme law of the land" - but only treaties "made ... under the authority of the United States"; that is, treaties that make commitments within the scope of federal power. A treaty that goes beyond the scope of preexisting federal authority is thereby itself unconstitutional, not simply a valid treaty that Congress lacks the power to implement. This distinction is important, because, under Scalia's approach, the president and the Senate would still be able to expand federal power by using "self-executing" treaties that do not require additional legislation to implement. Such treaties can be enforced by litigation in federal courts.

Thomas' position also has a weakness. His theory implies that the federal government cannot sign treaties on matters within the scope of Congress' Article I powers, if the issue in question is not a "matter of international intercourse." As Thomas recognizes, that is a very vague standard. But it is also wrong because there is no constitutional problem with a treaty that covers a "non-international" matter within the scope of congressional power. Just as an individual can sign a valid contract committing himself on an issue that would normally be considered purely personal, so a government can sign a treaty committing itself on a matter that would normally be considered purely local, so long as the government has the authority to regulate that conduct.

Modern treaties and proposed treaties target an incredibly wide range of issues. To take just one example, opponents of Colorado and Washington's recent legalization of marijuana claim that it is illegal because it supposedly violates international treaties banning the sale and possession of cannabis. A president and Senate could potentially use such treaties to override limits on federal power, perhaps by signing a treaty with a small foreign country dependent on American aid.

In the short run, even an unequivocal decision limiting the treaty power may have only a modest impact. Modern Supreme Court decisions already give the federal government expansive authority under its power to regulate interstate commerce, which has been interpreted so broadly as to allow Congress to use it to ban the possession of medical marijuana that has never crossed state lines or been sold in any market. But the court's overexpansive view of the Constitution's commerce clause has come under increasing attack in recent decades, and the justices have shown greater willingness to limit it, most recently in the 2012 Obamacare case. The more we begin to take seriously other constitutional limits on the scope of federal power, the greater the temptation to use treaties to get around these constraints.

The debate over the scope of the treaty power will surely continue, and may well return to the Supreme Court in the future. But Bond v. United States is an encouraging, though not definitive, sign that the court will not allow treaties to serve as an end-run around constitutional limits on federal authority.

Ilya Somin is a professor of law at George Mason University, and author of "Democracy and Political Ignorance: Why Smaller Government is Smarter" and "A Conspiracy Against Obamacare: The Volokh Conspiracy and the Health Care Case."