In its recent decision in Bond v. United States, the Supreme Court avoided deciding whether Congress, in executing a treaty, could exceed the enumerated powers to which the Constitution otherwise restricts it. For example, if a treaty requires a signatories to make it a crime to use a particular chemical, may Congress pass a law criminalizing the chemical’s use even though the Constitution gives Congress no general criminal jurisdiction?
The majority in Bond avoided the question by ruling, rather implausibly I think, that the plain words of the statute didn’t apply, so there was no need to decide whether Congress had authority to enact it. But the question will soon return.
Here’s what the Court has decided thus far:
* Because the Constitution gives Congress authority to pass laws “necessary and proper” to assist the President and Senate in making treaties, Congress can enact some measures pursuant to treaties that it could not pass otherwise. This was the rule laid down in Missouri v. Holland (1920). The Holland case said the Tenth Amendment does not prevent this, because the Tenth Amendment denies only unenumerated powers and the power to make necessary and proper laws to execute the treaty power is enumerated.
* Although the Congress may thereby exercise authority not otherwise on its list, Congress still may not violate specific rules imposed by the Constitution. Thus, Congress may not execute a treaty by passing an ex post facto law or a law violating the specific guarantees in the Bill of Rights. This was decided in Reid v. Covert (1956).
In recent years, several conservative and libertarian commentators have argued that when adopting laws enforcing treaties, Congress is limited to the powers explicitly enumerated. In other words, they argue that Missouri v. Holland was wrongly decided. In addition to citing federalism concerns, they point out that the Necessary and Proper Clause, when read with the Treaty Clause, gives power only to assist in the “making” of treaties, not carrying them out. So Congress may fund a negotiating team, but may not pass a law to enforce of the terms of treaty unless the law is otherwise authorized in the Constitution’s enumeration.
As a free market conservative, I find this argument appealing. Unfortunately, it is not convincing.
First, it seems to be an overly-restrictive reading of the Constitution’s language: surely the power to “make” a treaty on a particular topic implies an enforceable promise to carry it out. For example, the ability to acquire and cede territory has always been incident to the power to make treaties. Yet the power to acquire and cede territory is not otherwise enumerated in the Constitution. Does that mean that when we acquired Hawaii by treaty Congress could adopt no law to carry out the annexation? Some people point out that Thomas Jefferson thought a constitutional amendment necessary for acquiring territory. But he was clearly wrong about this: Jefferson was a very great man, but for reasons I discuss in my book, The Original Constitution: What It Actually Said and Meant, he was not a particularly reliable source of constitutional meaning (partly because was in France during the ratification debates).
Second, besides granting power to assisting the President to “make” treaties, the Constitution also grants Congress power to execute them. Specifically, the Constitution grants Congress authority “To make all Laws which shall be necessary and proper for carrying into Execution . . . all other Powers vested by this Constitution in the Government . . . or in any Department or Officer thereof.” Among those “other Powers” is the authority of the President to “take Care that the Laws be faithfully executed.” The Constitution adds that treaties, like the Constitution and statutes, are the “supreme Law of the Land.” So the text rather clearly authorizes Congress to pass statutes to enforce treaties. And it does not limit enforcement to enumerated powers. In fact, treaty enforcement is an enumerated power.
Finally, there is considerable evidence that the Founders themselves understood the treaty power to be a potential source of authority for Congress in addition to the items otherwise enumerated. They got this understanding from history, international law, and events they had witnessed themselves.
To cite only two illustrations of the evidence: (1) The Virginia ratifying convention featured extensive discussion of the power to acquire and cede territory incident to treaties, a power not otherwise enumerated, and (2) the Confederation Congress had ratified a treaty which potentially restricted religious freedom. (The First Amendment was passed in part to prevent this from happening again.) And those are only two illustrations. For more, see The Original Constitution: What It Actually Said and Meant.
There are limits, however: In acting under the Necessary and Proper Clause, Congress is executing only incidental powers—in other words, powers subordinate to those granted in the Constitution and tied to them by custom or necessity. So Congress’s authority to execute treaties would not extend to altering the entire federal system. Congress could not, pursuant to a treaty with Luxembourg, transfer the entire criminal law from the states to the federal government.
The U.S. is now a party to thousands of existing treaties. Just what Congress can and can’t do under them involves some very difficult questions. The Court dodged those questions in U.S. v. Bond, but will have to address them in the near future. Alternatively, we can adopt a constitutional amendment—such as the amendment suggested many years ago by Senator John W. Bricker of Ohio—clarifying the limits of Congress’s authority.
Since Congress is unlikely to propose an amendment limiting its own power (except for the repeal of Prohibition it has not done so since 1789), a convention of states would be necessary to propose such an amendment for the states to ratify.