The Constitution grants the President the power to make treaties by and with the advice and consent of the Senate. One persistent matter of debate is whether there are subject matter limits to the President's power to make treaties. In particular, in making an international agreement with a foreign nation, are there certain topics that are off limits? (1) For instance may the President make a treaty about the details of family law, a subject often thought beyond the authority of the federal government? (2) Or may the President make a treaty that obliges the United States to respect certain human rights, say a right to be free of corporal punishment? While many nuanced answers are possible, in the main, there are two primary answers: "no" and yes." (3)
Those who respond "no" to such questions suppose that the federal power to make treaties is not constrained by any subject matter limits. Their answer likely turns (in part) on their inability to detect subject matter constraints either in the Treaty Clause or elsewhere in the Constitution. Hence they conclude that the President, with the Senate's consent, can make treaties on any subject: commerce, tax, military alliances, the rights of aliens, territorial cessions, migratory birds, human rights, children's rights, and even animal rights. If the Republic of Panama sought a treaty with the United States relating to neighborhood watches, the President could make such a treaty, provided the Senate was unwise enough to consent with the requisite supermajority.
Those who answer "yes"--those who suppose that there are subject matter limits on the treaty power--likely trade upon a sense that there must be implied limits on what the President may cram into a treaty. The federal government is a government of exhaustively enumerated and (therefore) limited powers. After carefully expressing what the Congress may do in Article I, Section 8 and what the President may do in the rest of Article II, how can it be that the Treaty Clause surreptitiously conveys broad power to reach any and all subjects? Such thinking leads some to conclude that the Constitution imposes subject matter limits that are left unsaid.
I count myself in the first camp, among those who suppose that the Constitution contains no subject matter limits on the treaty power. More precisely, I believe that the original Constitution granted the President the power to make international agreements, with no particular constraints on the subjects they might touch. I reach this conclusion with a great deal of reluctance not because the case for this proposition is weak but because, as a matter of policy, I favor subject matter limits on the treaty power as a means of ensuring exclusive state authority over certain matters. Nonetheless, I have become convinced that the Constitution does not gratify my preferences. The treaty power is boundless in the sense that treaties of the United States can concern any subject, no matter how fanciful or seemingly absurd the matter might seem.
Yet the treaty power is not completely without bounds. There likely are constraints on federal power that apply regardless of the sort of power (legislative, executive, judicial) being exercised. Such constraints would likewise apply to the treaty power as well. 3
Part I canvasses possible subject matter limits on the treaty power. Part II discusses the Constitution's text. Part III considers subject matter limits on treaties prior to the Constitution's creation. Part IV examines how the Constitution constrains the treaty power that lacks subject matter bounds.
POSSIBLE SUBJECT MATTER LIMITS
The basic argument that the treaty power is boundless can be stated relatively succinctly, at least for now. In the eighteenth century, a treaty was a significant, durable contract or agreement between sovereigns. (4) The national government enjoys the power to make such contracts, without regard to subject matter, because the Constitution grants the power to make treaties without imposing any such constraints. Many (perhaps most) treaties of the United States have concerned matters that no one disputes are the proper subjects of treaties--alliances, commerce, etc. Some modern treaties of the United States seemingly have encroached upon new ground, embracing matters often not typically found in international agreements. (5) Those contracts with other nations that occupied new subject matter territory are no less treaties because they incorporate novel subjects not usually found in treaties. In a similar way, a contract made with my friend where I promise not to touch my nose and she promises to give me a dollar in consideration for this promise is no less a contract even if no one else has ever made such a fanciful contract. Because the federal government has the power to make treaties with other sovereigns, it has the power to make all sorts of contracts, sound as well as unsound pacts, serious as well as curious bargains.
Theories that imagine that the treaty power faces subject matter constraints require a bit more elucidation, at least to discern the bounds that the theories contemplate. I mention two different subject matter limits to give a sense of the possible, but these by no means exhaust the possibilities. Both are perhaps motivated by the sense, referenced earlier, that when we step back from the Constitution's text and consider its structure, we should conclude that it presupposes enclaves of exclusive state legislative authority. Family law, property law, the law of torts--were not these to be regulated by the respective states without federal interference? The Constitution is studded with too many signals that the federal government cannot regulate everything under the sun, even via the treaty power.
Subject matter limits on the treaty power can be classified as either internal or external. Internal restraints arise from something in the Constitution itself, usually structural inferences about enumeration or federalism. External restraints, though perhaps loosely grounded in the word "treaty," derive their force from something outside the Constitution, a sense that the international system limits the scope of treaties generally and hence acts as an implied (but no less real) check on the President's ability to make treaties.
Consider a theory of internal restraint, namely that because Article I, Section 8 enumerates federal legislative power and because the treaty power seems something of a substitute for ordinary federal lawmaking, we ought to regard the treaty power's scope as coterminous with the grants to Congress. This theory of the scope of the treaty power would presumably rest upon the view that having painstakingly listed eighteen grants of legislative power in Article I (6) and a handful of legislative authorities elsewhere, (7) all resting with Congress, no sensible constitution maker would grant the President, acting with the Senate, the power to make international agreements relating to matters beyond these specific grants. (8) No rational constitution maker would do this because it would render the system of enumerated powers something of a farce. Even if Congress could not legislate in some areas like property law or inheritance, the President could, with the Senate's consent, make international contracts related to such subjects. Having enumerated so many (but not all) legislative subjects, the Constitution leaves the unenumerated subjects to the states.
External theories suppose that the treaty power's subject matter limits are to be discerned by reference to what are the proper subjects of treaties in the international arena. In other words, international law or the practices and customs of treatymaking implicidy restrain the treaty power of the United States. Sometimes this goes by the claim that treaties must relate to matters of "international concern." (9) Because constraints on treaties come from the international realm, they have no necessary relationship to the legislative grants to Congress. Federal treaties might cover some areas in which Congress can legislate (e.g., commerce, bankruptcy), and they might extend to some topics that Congress cannot (e.g., alliances and the rights of resident aliens).
To complicate matters, subjects of "international concern" can be a static or dynamic concept. The dynamic version asks what is a matter of international concern today. Whatever is such a matter is a proper subject for treaties made today even if the subject was not a matter of international concern in the eighteenth, nineteenth or twentieth centuries. Even if no human rights treaties were made in the eighteenth century, such treaties can be made today because human rights are now a matter of international concern given the pervasive interest of countries to contract about how nations treat their own nationals.
The static view reads the Treaty Clause as providing that the President may make treaties on subjects that were a matter of international concern in the late eighteenth century. If a subject is a matter of international concern today, but was not an international matter in the late eighteenth century, then the President cannot make a treaty on the subject, no matter its weighty international significance today. Contrariwise, if something is no longer a matter of international concern, but was a matter of international interest in the eighteenth century, the President could make a treaty on that now marginalized and long disregarded topic.
Because I believe there are no subject matter limits particular to the treaty power, I won't further explore theories that read the treaty power as constrained to certain subjects. Instead, in the sections that follow, I lay out the textual, structural, and historical argument that the Constitution neither imposes (nor incorporates) any subject matter limits particular to the scope of the treaty power.
To adumbrate the argument, prior to the...