Article II, Section 2, Clause 2 — Treaty-Making Power

ArtII.S2.C2.1.1 Overview of President’s Treaty-Making Power

In the Treaty Clause, the Constitution returns to the realm of foreign affairs and vests the power to make treaties in the national government. Earlier in the Constitution, Article I prohibits the states from concluding treaties and limits the states’ role in other forms of international relations.¹ Article I also assigns several foreign affairs-related powers to the Legislative Branch, including powers to regulate commerce with foreign nations, define and punish offenses against the Law of Nations and on the high seas, and regulate many aspects of the military.² In Article II’s Treaty Clause, the Constitution, for the first time, addresses international affairs from the vantage of the President’s powers. The clause vests the President, acting with the advice and consent of the Senate, with the authority to make treaties for the United States.

Treaties—which the Supreme Court traditionally defines as pacts among sovereign countries³—have been tools of international relations since antiquity.⁴ After the United States won its independence from Great Britain, many Americans viewed the Articles of Confederation as a form of a treaty among the individual states of the union.⁵ But the Framers criticized how the Articles of Confederation addressed the new union’s treaty obligations to foreign countries.⁶ The Articles lacked a mechanism to ensure individual states complied with the United States’ international obligations, particularly its obligations to England under the 1783 Treaty of Peace that ended the Revolutionary War.⁷ When drafting the Constitution, the Framers sought to remedy this problem by including treaties among the sources of the “supreme Law of the Land” in the Supremacy Clause.⁸ Because of this change, treaties occupy a unique place in the constitutional system: they can operate simultaneously as domestic law of the United States and as tools of foreign policy in the form of pacts between nations.⁹

Elements of the treaty-making process may vary depending on the treaty, but the standard process generally operates as follows:¹⁰ a member of the Executive Branch negotiates the terms of a treaty, and the President or another Executive Branch official signs the completed draft when negotiations conclude.¹¹ Next, the President submits the treaty to the Senate.¹² If “two thirds of the Senators present” pass a resolution of advice and consent, the process shifts back to the Executive Branch.¹³ At this stage, the President decides whether to make the final decision to enter the treaty on behalf of the United States.¹⁴ It is thus the President, and not the Senate, who has final responsibility for completing the treaty-making process.¹⁵ However, the President has no obligation to ratify a Senate-approved treaty, and, in some cases, the President has declined to do so.¹⁶

Although many important events in U.S. foreign relations have culminated in treaties,¹⁷ the United States does not conclude all agreements with foreign nations through the process outlined in the Treaty Clause. The President regularly enters into executive agreements, which do not receive the Senate’s advice and consent, and “political commitments” and other nonlegal pacts that are not intended to be binding.¹⁸ Since the turn of the twentieth century, Presidents have increasingly used alternatives to treaties,¹⁹ which are examined in the discussion of the President’s inherent power over foreign affairs.²⁰ The following essay focuses on treaties in the constitutional sense, meaning international agreements²¹ that the President concludes after receiving the Senate’s advice and consent through the process defined in the Treaty Clause.²²

ArtII.S2.C2.1.2 Historical Background on Treaty-Making Power

Jurists, courts, and legal analysts have long viewed a country’s capacity to enter into international pacts as an essential element of national sovereignty.¹ Under the British system of treaty-making, the power to conclude and ratify treaties falls within the prerogative of the Crown.² After the United States achieved its independence from Great Britain, the treaty-making power was transferred to the newly established Congress under the Articles of Confederation.³ But the United States soon faced practical difficulties in attempting to negotiate treaties through a large legislative body.⁴ And even when the national government was able to conclude treaties, the new nation often found itself unable to perform its treaty obligations without the cooperation of the state governments.⁵

By the time of the Constitutional Convention, the delegates had largely come to agree that the national government required a stronger power to enforce treaties throughout the United States, but there were many differences of opinion as to where the newly enhanced treaty power should reside.⁶ In August 1787, the Committee of Detail proposed an early draft of the Constitution that would have provided the Senate alone with the power to make treaties.⁷ But the delegates raised widespread objections to the provision.⁸ Some delegates proposed that treaty-making include a role for the President or be granted to the President exclusively.⁹ Others argued that both chambers of Congress should be included in the process.¹⁰ Ultimately, the delegates decided that the Executive Branch was best equipped to act with the confidentiality and efficiency necessary for treaty negotiations.¹¹ In the Federalist No. 64, John Jay expanded on this rationale, arguing that individuals with useful information in treaty negotiations would “rely on the secrecy of the President, but . . . would not confide in that of the Senate, and still less in that of a large popular Assembly.”¹²

While the delegates to the Constitutional Convention concluded that the President should play a role in treaty-making, they also decided that no single component of the government should have the power to bind the United States to a treaty.¹³ Because of treaties’ dual nature as tools of foreign policy and part of the law of the land, the Federalist Papers describe treaty-making as a “peculiar” combination of two functions that did not fit neatly into the founding era understanding of separation of powers.¹⁴ In the Federalist Papers, Alexander Hamilton and John Jay argued that treaty-making contains elements of executive power because it involves diplomacy and the management of foreign relations.¹⁵ Hamilton and Jay also believed treaty-making invokes the legislative power because treaties can have the force of domestic law.¹⁶ As Hamilton summarized in the Federalist No. 75, the power to make treaties belongs “neither to the legislative nor to the executive.”¹⁷ For that reason, the delegates to the Constitutional Convention saw fit to divide this dual natured power between dual branches.¹⁸

The delegates chose to include the Senate in the treaty-making process rather than the House of Representatives because they believed the House would be too large and that its membership would change too often to act with the secrecy and speed necessary for treaty-making.¹⁹ The delegates also believed the Senate would represent and protect the interests of the states,²⁰ which the Constitution denies the power to make treaties.²¹

The delegates viewed the requirement that a supermajority of two thirds of Senators present provide their advice and consent as a method to prevent the federal government from making treaties that would promote regional interests or discriminate against a minority of states.²² In particular, the Southern states were concerned that the federal government would give Spain navigation rights on the Mississippi River, which were essential to the Southern economy, in exchange for trade concessions that would benefit the Northern economy.²³ And the Northern states feared they could lose access to fisheries in Newfoundland through a treaty.²⁴ The Treaty Clause’s supermajority requirement—one of several in the Constitution²⁵—was designed to alleviate these concerns by allowing a minority of states, through their representatives in the Senate, to block treaties that could disproportionately disadvantage segments of the nation.²⁶

The exact number of Senators required to approve a treaty under the Treaty Clause differs from its predecessor provision in the Articles of Confederation. Whereas the Articles of Confederation required nine of thirteen states to approve all treaties, the Framers deliberately changed the advice and consent threshold to “two thirds of the Senators present[.]”²⁷ Hamilton explained in the Federalist No. 75 that the change from a fixed number to a percentage would account for the possibility that new states would join the union.²⁸ Hamilton also argued that it would limit individual Senators’ ability to block a treaty simply by declining to appear in the Senate for a vote.²⁹ And whereas each state voted as a unit under the Articles, the Treaty Clause permits Senators to vote individually, creating the possibility that one state’s Senator could vote for a treaty and the other against it.³⁰

Many scholars have concluded that the Framers intended “advice” and “consent” to be separate aspects of the treaty-making process, although there is still some debate on the issue.³¹ According to the prevailing interpretation, the “advice” element required the President to consult with the Senate during treaty negotiations before seeking the Senate’s final “consent.”³² President George Washington appears to have understood that the Senate had such a consultative role,³³ but he and other early Presidents soon declined to seek the Senate’s input during the negotiation process.³⁴ In modern treaty-making practice, the Executive Branch generally is responsible for negotiations, and the Supreme Court stated in dicta that the President’s power over treaty negotiations is exclusive.³⁵

Although Presidents since Washington have not formally consulted with the Senate as a body, the Senate maintains an aspect of its “advice” function through its conditional consent authority.³⁶ In considering when to provide its advice and consent to a treaty, the Senate may condition its approval on reservations,³⁷ declarations,³⁸ understandings,³⁹ and provisos⁴⁰ concerning the treaty’s application.⁴¹ Under established U.S. practice, the President cannot ratify a treaty unless the President accepts the Senate’s conditions.⁴² If accepted by the President, these conditions may modify or define U.S. rights and obligations under the treaty.⁴³ The Senate also may propose to amend the text of the treaty itself, after which other nations that are parties to the treaty must consent to the changes for them to take effect.⁴⁴

ArtII.S2.C2.1.3 Scope of Treaty-Making Power

The Articles of Confederation limited the scope of the treaty power by carving out two acts that the United States could not take in a treaty: limiting the states’ power to impose “imposts on duties on foreigners” and “prohibiting the exportation or importation of any species of goods or commodities whatsoever[.]”¹ The Constitution’s Treaty Clause, by contrast, contains no such restrictions.² During the Constitutional Convention and the ratification debates, some delegates expressed concern that the treaty power was too broad and subject to abuse.³ But James Madison and others defended the structure of the treaty power, arguing that it was not possible to enumerate all circumstances in which the government could misuse the treaty power,⁴ and that other checks and balances would provide appropriate limitations.⁵ In the end, the Framers did not include express limitations in the Treaty Clause on the types of subjects that may be addressed in a treaty.⁶

Despite the absence of subject matter limitations in the Treaty Clause’s text, there have been suggestions since the founding era that the treaty-making power is implicitly limited to matters that traditionally have been the subject of intercourse between sovereign nations.⁷ The status and scope of such a limitation, however, remains unclear. In several cases from the turn of the nineteenth century, the Supreme Court stated that the treaty power is not limited to a set of enumerated subjects in the way that Congress’s legislative powers are so constrained.⁸ Yet, in those same cases, the Court suggested that the treaty power might only extend to topics that “properly pertain” to foreign relations⁹ or are the “proper subjects”¹⁰ of negotiations between the United States and foreign nations.

Some jurists and commentators assert that the only proper subjects for treaties under the Constitution are “matters of international concern.”¹¹ Under this view, treaties must relate to “external concerns,” as distinguished from “purely internal” subjects.¹² In 2014, three Supreme Court Justices joined a concurring opinion arguing that the treaty power “can be used to arrange intercourse with other nations, but not to regulate purely domestic affairs.”¹³ But the Court has not ruled on the issue, and there is no consensus on whether the Constitution contains such a limitation.¹⁴ Nor has the Supreme Court defined what, if any, matters are insufficiently international in nature to be an improper subject for a treaty.

To the extent there once was a common understanding of the line between internal and external matters, changes in international treaty practice have complicated this distinction.¹⁵ Early U.S. treaties often were bilateral and addressed matters such as relations with Indian tribes,¹⁶ military alliances, international trade, and military neutrality.¹⁷ But treaties have expanded greatly in number and in the scope of their subject matter since World War II.¹⁸ Treaties often now take the form of multilateral instruments that address matters that were not common subjects of international intercourse during the founding era, such as environmental protection and human rights.¹⁹ Scholars actively debate whether the Constitution limits the scope of modern treaties and multilateral instruments to “international” matters.²⁰

ArtII.S2.C2.1.4 Self-Executing and Non-Self-Executing Treaties

The Supremacy Clause of the Constitution, Article VI, Clause 2, states that treaties concluded in accordance with constitutional requirements have the status of the “supreme Law of the Land[.]”¹ The Founders included treaties in the Supremacy Clause in direct response to one of the major weaknesses of the Articles of Confederation: the national government’s inability to enforce the United States’ treaty obligations.² Although the Articles of Confederation gave exclusive treaty-making power to Congress,³ the United States depended on state legislatures to enact laws necessary to ensure compliance with the Nation’s treaty commitments.⁴ When states ignored or violated the United States’ obligations—most famously, by refusing to permit British citizens’ to collect pre-Revolutionary War debts⁵—some foreign nations considered the United States an unreliable treaty partner⁶ or cited U.S. noncompliance as grounds to disregard their own treaty commitments.⁷ The Framers sought to remedy this problem by making treaties part of the “supreme Law of the Land” to which “the Judges in every State shall be bound[.]”⁸ The Supremacy Clause marked a shift from the British system under which treaties generally have domestic effect only after being implemented by Parliament.⁹

Despite the Supremacy Clause’s seeming simplicity, not all treaties have the status of domestic law that is enforceable in U.S. courts.¹⁰ Some treaties or (provisions within treaties¹¹) are “self-executing,” meaning domestic courts can enforce them directly.¹² Other treaty provisions are “non-self-executing” and occupy a more complex status in the U.S. legal system.¹³ Non-self-executing treaty provisions are not directly enforceable in U.S. courts, and Congress generally must pass legislation implementing the provision in a domestic statute to make it judicially enforceable.¹⁴

The Supreme Court first recognized the self-execution dichotomy in an 1829 decision, Foster v. Neilson.¹⁵ In his opinion for the Court, Chief Justice John Marshall explained: “[o]ur [C]onstitution declares a treaty to be the law of the land. It is, consequently to be regarded in courts of justice as equivalent to an act of the legislature[.]”¹⁶ But Chief Justice Marshall then immediately qualified this explanation, stating that a treaty is only the equivalent of a legislative act when the treaty “operates of itself without the aid of any legislative provision.”¹⁷ When the terms of treaty “import a contract” or suggest that some future legislative act is necessary, Marshall explained, “the treaty addresses itself to the political, not the judicial department; and the legislature must execute the contract before it can become a rule for the Court.”¹⁸ Using this test, the Foster Court held that the treaty provision at issue—which stated that certain land grants from the King of Spain “shall be ratified and confirmed”—was non-self-executing because it suggested that Congress would ratify the land grants through a future legislative act.¹⁹

The Supreme Court revisited the self-execution doctrine in a 2008 decision, Medellín v. Texas.²⁰ In that case, the United Nation’s principal judicial body, the International Court of Justice (ICJ), had entered a judgment directing the United States to reconsider the criminal convictions and sentences of a group of Mexican nationals.²¹ The ICJ concluded that U.S. state and local authorities had not afforded the foreign nationals their rights to communicate with Mexican consular officials as required by the Vienna Convention on Consular Relations.²² One of the foreign nationals, Ernesto Medellín, argued that the ICJ’s judgment was directly enforceable in U.S. courts because of a provision in another treaty, Article 94 of the Charter of the United Nations. That article provides that the United States (and any member nation of the United Nations) “undertakes to comply with the decision of the [ICJ] in any case to which it is a party.”²³ Medellín argued that Article 94 required Texas state authorities to reevaluate his conviction and stay his upcoming execution, but the Supreme Court disagreed.²⁴ The Court held that Article 94 of the Charter of the United Nations was not self-executing, in part, because Article 94 states that a party to the Charter “undertakes to comply” with ICJ decisions, rather than stating that a country “shall” or “must” comply.²⁵ Article 94 was not self-executing because it was not “a directive to domestic courts” and could not be judicially enforced in the face of contrary state law, the Supreme Court concluded.²⁶

Determining whether a treaty provision is self-executing is not always a straightforward task.²⁷ In some cases, a treaty may specify whether it is intended to be given immediate domestic legal effect without further action.²⁸ However, the Medellín Court disapproved of the notion that certain special words or phrases are necessary to make a treaty self-executing.²⁹ Medellín also rejected a multi-factor analysis, advanced by three Justices in a dissent, which would look outside the treaty’s text and analyze a variety of “practical, context-specific criteria”³⁰ to determine self-execution.³¹ Instead, the Medellín Court explained that the primary question is whether the President and Senate intended the treaty to be self-executing.³² The Supreme Court has deemed a treaty non-self-executing when the text manifested an intent that the treaty would not be directly enforceable in U.S. courts,³³ or when the Senate conditioned its advice and consent on the understanding that the treaty was non-self-executing.³⁴ Other relevant factors include whether the treaty provisions are suitably precise or obligatory to be capable of judicial enforcement and whether the provision contemplates that implementing legislation or other legal measures, such as administrative action, will follow the treaty’s ratification.³⁵

Many courts and commentators agree that treaty provisions that would require the United States to exercise authority that the Constitution assigns to Congress exclusively must be deemed non-self-executing.³⁶ Although the Supreme Court has not addressed these constitutional limitations, lower courts have concluded that, because Congress controls the power of the purse,³⁷ a treaty provision that requires expenditure of funds must be treated as non-self-executing.³⁸ Other lower courts have suggested that treaty provisions that purport to create criminal liability³⁹ or raise revenue⁴⁰ must be non-self-executing because those powers are the exclusive prerogative of Congress.

The doctrine of non-self-execution appears to be in some tension with the Supremacy Clause’s declaration that “all treaties” are part of the supreme law of the land.⁴¹ The Supreme Court has never fully explained the relationship between non-self-executing treaties and the Supremacy Clause.⁴² Opinions from some lower courts and the Office of Legal Counsel (OLC) in the Department of Justice⁴³ suggest non-self-executing treaties lack any domestic legal status.⁴⁴ However, other courts and scholars contend that, although non-self-executing treaties may not be enforced in courts, they may still form part of the supreme law of the land that is carried out and enforced outside the judicial system.⁴⁵

Despite the importance of the self-execution doctrine in U.S. domestic law, self-execution does not impact treaties’ status under international law.⁴⁶ Under international law, treaties create rights and obligations that nations owe to one another that are independent of each nation’s domestic law.⁴⁷ International law generally allows each country to decide how to implement its treaty commitments into its own domestic legal system.⁴⁸ The self-execution doctrine concerns domestic enforcement of treaties, but it does not affect the United States’ obligation to comply with the provision under international law.⁴⁹ Thus, even if courts cannot enforce a treaty provision in domestic courts because it is non-self-executing, that provision may still be binding under international law, and the United States may still have an international legal obligation to comply.

ArtII.S2.C2.1.5 Congressional Implementation of Treaties

When a treaty provision requires implementing legislation or appropriation of funds to carry out the United States’ obligations, the task of providing that legislation falls to Congress.¹ In the early years of constitutional practice, debate arose over whether Congress was obligated—rather than simply empowered—to enact legislation implementing non-self-executing treaty provisions into domestic law.² But the issue has not been resolved in any definitive way.³

By contrast, the Supreme Court did address the scope of Congress’s power to enact legislation implementing a treaty in a 1920 case. In Missouri v. Holland,⁴ the Supreme Court considered a constitutional challenge to a federal statute that implemented a treaty prohibiting the killing, capturing, or selling of certain birds that traveled between the United States and Canada.⁵ In the preceding decade, two federal district courts had held that similar statutes enacted prior to the treaty violated the Tenth Amendment because they infringed on the reserved powers of the states to control natural resources within their borders.⁶ But the Holland Court determined that, even if those district court decisions were correct, their reasoning no longer applied once the United States concluded a valid migratory bird treaty.⁷ In an opinion authored by Justice Oliver Wendell Holmes, the Holland Court concluded that the federal government can use the treaty power to regulate matters that the Tenth Amendment otherwise might reserve to the states.⁸ And if the treaty itself is constitutional, the Holland Court held, Congress has the power under the Necessary and Proper Clause⁹ to enact legislation implementing the treaty into domestic law of the United States without restraint by the Tenth Amendment.¹⁰

Some legal commentators and jurists have questioned aspects of the Justice Holmes’s reasoning in Holland.¹¹ Some of Holland’s critics contend that the decision gives the federal government too broad a power to legislate in areas reserved to the states, especially when coupled with twentieth century changes in international lawmaking that have expanded the types of issues addressed in treaties.¹² Others argue that a combined reading of the Necessary and Proper Clause and the Treaty Clause only permits Congress to pass laws necessary to make treaties, not to implement them, as Justice Holmes reasoned.¹³ Under this view, Congress could use the Necessary and Proper Clause to, for example, appropriate funds for U.S. diplomats to engage in overseas treaty negotiations, but Congress must rely on its other Article I powers to implement treaties that have been signed and ratified.¹⁴ Other legal scholars respond to these critiques by contending that the power to make treaties is hollow without the power to implement them,¹⁵ that political and structural checks safeguard federalism,¹⁶ and that Holland comports with the Constitution’s text and historical practice.¹⁷

As the academic debate continues, the Supreme Court has not overturned Holland’s holding related to Congress’s power to implement treaties.¹⁸ Rather, the Court has sometimes discussed it favorably.¹⁹ Nevertheless, principles of federalism embodied in the Tenth Amendment continue to influence constitutional challenges to U.S. treaties and their implementing statutes, including in the 2014 Supreme Court decision, Bond v. United States.²⁰

Bond concerned a criminal prosecution arising from a case of “romantic jealousy” when a jilted spouse spread toxic chemicals on the mailbox of a woman with whom her husband had an affair.²¹ Although the victim only suffered a minor thumb burn, the United States brought criminal charges under the Chemical Weapons Convention Implementation Act of 1998—a federal statute that implemented a multilateral treaty prohibiting the use of chemical weapons.²² The accused asserted that the Tenth Amendment reserved the power to prosecute her “purely local” crime to the states, and she asked the Court to overturn or limit Holland’s holding on the relationship between treaties and the Tenth Amendment.²³

A majority in Bond declined to revisit Holland’s interpretation of the Tenth Amendment,²⁴ but the Bond Court ruled in the accused’s favor based on principles of statutory interpretation.²⁵ When construing a statute interpreting a treaty, Bond explained, “it is appropriate to refer to basic principles of federalism embodied in the Constitution to resolve ambiguity in a federal statute”²⁶ Applying these principles through a presumption that Congress did not intend to intrude on areas of traditional state authority, the Bond Court held that the Chemical Weapons Convention Implementation Act did not apply to the jilted spouse’s actions.²⁷ In other words, the majority in Bond did not disturb Holland’s conclusion that the Tenth Amendment does not limit Congress’s power to enact legislation implementing treaties, but Bond did hold that principles of federalism reflected in the Tenth Amendment may dictate how courts interpret such implementing statutes.²⁸

ArtII.S2.C2.1.6 Interpreting Treaties

All three branches of government play a part in treaty interpretation. When analyzing a treaty for purposes of applying it as domestic law of the United States, U.S. courts have final authority to interpret the treaty’s meaning.¹ The Supreme Court has stated that its goal in interpreting a treaty is to discern the intent of the nations that are parties to the treaty.² The interpretation process begins by examining “the text of the treaty and the context in which the written words are used.”³ When a treaty provides that it is to be concluded in multiple languages, the Supreme Court has analyzed foreign language versions to help understand the treaty’s terms.⁴ The Court also considers the broader “object and purpose” of a treaty.⁵ In some cases, the Supreme Court examines extratextual materials, such as drafting history,⁶ the views of other state parties,⁷ and the post-ratification practices of other nations.⁸ But the Court has cautioned that consulting sources outside the text may not be appropriate when the treaty is unambiguous.⁹

The Executive Branch also plays a role in interpreting treaties, especially outside the context of domestic litigation and when operating in the realm of international affairs. The Executive Branch generally is responsible for carrying out treaties’ requirements and determining whether other countries fulfill their obligations to the United States.¹⁰ In performing this role, the Executive Branch often must interpret treaties’ provisions and mandates.¹¹ In addition, some questions of treaty interpretation may involve presidential discretion or otherwise may present “political questions” that are more appropriately resolved in the political branches than in the courts.¹²

Within the Executive Branch, the Department of Justice participates in treaty interpretation as part of its statutory responsibilities to provide legal opinions within the Executive Branch¹³ and represent the United States in litigation.¹⁴ The Department of State, which oversees treaty negotiations,¹⁵ often is able to provide authoritative interpretations based on its access to information about negotiating history and the views of treaty partners.¹⁶ Because the Executive Branch may have special insight into a treaty’s meaning, the Supreme Court has stated that the Executive Branch’s views are entitled to “great weight.”¹⁷ But the Court has not adopted the Executive Branch’s interpretation in every case.¹⁸ And interbranch disputes may arise if the Executive Branch changes its interpretation and departs from the shared understanding of the executive and the Senate at the time of ratification.¹⁹

The Legislative Branch also influences treaty interpretation. The Senate may directly shape interpretation during the advice-and-consent process by making its consent to ratification conditioned upon a particular understanding of a treaty’s terms.²⁰ The President may not ratify a treaty unless he accepts the Senate’s interpretation or the Senate agrees to withdraw it.²¹ After the advice-and-consent process, however, the Senate’s ability to influence treaty interpretation is more restrained. According to a 1901 Supreme Court decision, Senate resolutions that purport to interpret a treaty after ratification are “without legal significance” because the “meaning of the treaty cannot be controlled by subsequent explanations of some of those who may have voted to ratify it.”²² That said, the Legislative Branch may still play a role in treaty interpretation when it passes implementing legislation or other treaty-related laws.²³ For example, when treaties require countries to ensure certain actions are criminalized in domestic law, Congress might interpret the treaty during the legislative process when it defines the prohibited actions in U.S. law; determines appropriate punishments; and decides whether domestic law already prohibits the conduct.²⁴

ArtII.S2.C2.1.7 Legal Effect of Treaties on Prior Acts of Congress

The Constitution provides that both federal statutes and treaties are part of the supreme law of the land, but it does not define the relationship between federal legislation and treaties.¹ As a result, disputes have arisen over which law governs when there are differences between a self-executing treaty and a federal statute. The Supreme Court has resolved this issue through what has become known as the “last-in-time” or “later-in-time” rule: when there is a conflict between a self-executing treaty and a federal statute, U.S. courts must apply whichever of the two reflects the “latest expression of the sovereign will” of the United States.²

The Supreme Court has frequently applied the last-in-time rule to give effect to a statute that conflicts with an earlier ratified treaty.³ Although the situation has arisen less often, the Supreme Court has also held that a treaty can override an earlier-in-time federal statute.⁴ The last-in-time rule, however, only applies when the treaty at issue is self-executing.⁵ Because a non-self-executing treaty is not judicially enforceable,⁶ courts will apply a federal statute over a non-self-executing treaty regardless of the timing of the statute’s enactment.⁷

ArtII.S2.C2.1.8 Preemptive Effect of Treaties

One of the Framers’ primary objectives in including treaties in the Supremacy Clause was to ensure that the United States’ treaty obligations would prevail over inconsistent state legislation.¹ During the pre-constitutional period, some states resisted complying with the 1783 Treaty of Peace with Great Britain, which prohibited the United States from placing “legal impediments” on British citizens’ attempts to collect pre-Revolutionary War debts.² Soon after the states adopted the Constitution, the Supreme Court addressed whether this treaty obligation would prevail over a state statute that allowed Virginians to satisfy debts to British creditors by making payment to a state loan office rather than to the creditors themselves.³ In Ware v. Hylton—the first Supreme Court case to address the legal effect of treaties—the Court struck down the Virginia law on the ground that it conflicted with the Treaty of Peace.⁴ “A treaty cannot be the Supreme law of the land, that is of all the United States, if any act of a State Legislature can stand in its way[,]” Justice Samuel Chase explained.⁵

Since Ware, the Supreme Court has held that treaty provisions preempt contrary state or local laws on many occasions.⁶ But just as only self-executing treaty provisions can prevail over earlier-in-time federal statutes, a treaty provision must be self-executing to preempt inconsistent state law.⁷ Before the mid-twentieth century, courts routinely held that treaties displaced state or local law without examining closely whether the treaty provision was self-executing.⁸ But in more recent cases, courts have closely considered whether a treaty provision is self-executing before applying it to preempt state law.⁹

ArtII.S2.C2.1.9 Effect of Treaties on the Constitution

While treaties may preempt contradictory state law and supplant earlier-in-time federal legislation, the treaty power is not so broad as to override the Constitution.¹ The Supreme Court stated in dicta in several cases that treaties may not alter the Constitution or authorize acts that the Constitution expressly prohibits.² Although the Court has never invalidated a treaty itself on constitutional grounds,³ it has held that courts may not give treaties domestic effect in a way that interferes with individual rights guaranteed in the Constitution.⁴ In Boos v. Berry, the Supreme Court held that a treaty-based obligation to protect foreign embassies did not authorize Congress to enact legislation that infringed on individuals’ First Amendment right to freedom of speech.⁵ Similarly, in Reid v. Covert, a plurality of the Court determined that the United States could not rely on international agreements as authority to conduct criminal proceedings that did not comply with the grand-jury and jury-trial guarantees in the Fifth and Sixth Amendments.⁶ The Supreme Court has since cited the Reid plurality opinion and described its conclusions related to the constitutional constraints on the treaty power as “well established.”⁷

ArtII.S2.C2.1.10 Breach and Termination of Treaties

The Constitution sets forth a definite procedure by which the President has the power to make treaties with the advice and consent of the Senate, but it is silent on who has the power to terminate them and how this power should be exercised.¹ The United States terminated a treaty under the Constitution for the first time in 1798. On the eve of possible hostilities with France, Congress passed, and President John Adams signed, legislation stating that four U.S. treaties with France “shall not henceforth be regarded as legally obligatory on the government or citizens of the United States.”² When he was Vice-President, Thomas Jefferson referred to the episode as support for the notion that only an “act of the legislature” can terminate a treaty.³ But commentators have since come to view the 1798 statute as a historical anomaly because it is the only instance in which Congress purported to terminate a treaty directly through legislation without relying on the President to provide a notice of termination to the foreign government.⁴ Moreover, because the 1798 statute was part of a series of congressional measures authorizing limited hostilities against the French Republic, some view the statute as an exercise of Congress’s war powers rather than precedent for a permanent congressional power to terminate treaties.⁵

During the nineteenth century, government practice treated the power to terminate treaties as shared between the Legislative and Executive Branches.⁶ Congress often authorized⁷ or instructed⁸ the President to provide notice of treaty termination to foreign governments during this time. On rare occasions, the Senate alone passed a resolution authorizing the President to terminate a treaty.⁹ Presidents often complied with the Legislative Branch’s authorization or direction,¹⁰ although they sometimes resisted attempts to compel termination of specific articles in treaties when the treaties did not authorize partial termination.¹¹ On other occasions, Congress or the Senate approved the President’s termination after-the-fact, when the Executive Branch had already provided notice of termination to the foreign government.¹²

At the turn of the twentieth century, a new form of treaty termination emerged: unilateral termination by the President without approval by the Legislative Branch. This method first occurred in 1899, when the McKinley Administration terminated certain articles in a commercial treaty with Switzerland,¹³ and then again in 1927, when the Coolidge Administration withdrew the United States from a convention to prevent smuggling with Mexico.¹⁴ During the Franklin Roosevelt Administration and World War II, unilateral presidential termination increased markedly.¹⁵ Although Congress at times enacted legislation authorizing or instructing the President to terminate treaties during the twentieth century,¹⁶ unilateral presidential termination became the norm.¹⁷

Some scholars and Members of Congress have challenged the President’s assertion of unilateral authority to terminate treaties under the rationale that treaty termination is analogous to the termination of federal statutes.¹⁸ Because domestic statutes may be terminated only through the same process in which they were enacted¹⁹—i.e., through a majority vote in both houses and with the signature of the President or a veto override—these observers contend that treaties likewise must be terminated through a procedure that resembles their making and that includes the Legislative Branch.²⁰ On the other hand, treaties do not share every feature of federal statutes. Whereas statutes can be enacted over the President’s veto, treaties can never be concluded without the President’s final act of ratification.²¹ Moreover, some argue that, just as the President has some unilateral authority to remove Executive Officers who were appointed with senatorial consent,²² the President may unilaterally terminate treaties made with the Senate’s advice and consent.²³

The President’s exercise of treaty termination authority has not generated opposition from the Legislative Branch in most cases, but there have been occasions in which Members of Congress sought to block unilateral presidential action. In 1978, a group of Members filed suit in Goldwater v. Carter²⁴ seeking to prevent President Jimmy Carter from terminating a mutual defense treaty with the government of Taiwan²⁵ as part of the United States’ recognition of the government of mainland China.²⁶ A divided Supreme Court ultimately ruled that the litigation should be dismissed, but it did so without reaching the merits of the constitutional question and with no majority opinion.²⁷ Citing a lack of clear guidance in the Constitution’s text and a reluctance “to settle a dispute between coequal branches of our Government each of which has resources available to protect and assert its interests[,]” four Justices concluded that the case presented a nonjusticiable political question.²⁸ This four-Justice opinion, written by Justice William Rehnquist, has proven influential since Goldwater, and federal district courts have invoked the political question doctrine as a basis to dismiss challenges to unilateral treaty terminations by President Ronald Reagan²⁹ and President George W. Bush.³⁰

Regardless of whether constitutional disputes over treaty termination are resolved in federal courts or through the political process, the power of treaty termination may depend on the specific features of the treaty at issue.³¹ For example, if termination of a particular treaty implicates the exercise of independent executive powers—such as the power to recognize foreign governments³²—the President perhaps may have a stronger claim to unilateral authority.³³ On the other hand, if the Senate were to condition its advice and consent to a treaty on a requirement that termination only occur with the approval of the Legislative Branch, some commentators argue that the President would be bound by that condition.³⁴ Finally, when Congress has passed legislation implementing a treaty into domestic law of the United States, the President likely lacks the authority to terminate the domestic effect of that legislation without going through the full legislative process for repeal of the statute.³⁵

A party’s breach of treaty obligations also can affect termination and withdrawal. Under international law, a party may suspend or terminate a treaty if another party materially breaches its obligations.³⁶ The Supreme Court has appeared to recognize that, at least in the absence of direction from Congress, the President has the power to deem a treaty that has been breached by a foreign nation void and therefore no longer binding.³⁷ The Court also has stated that Congress possesses the power to breach and abrogate a treaty by passing later-in-time legislation that conflicts with U.S. treaty obligations.³⁸

When considering all elements of the treaty-making process, the treaty power remains an area in which all three branches of government shape constitutional practice and influence foreign relations. The Judicial Branch determines treaties’ effect on domestic law and enforces self-executing treaty provisions in U.S. courts.³⁹ Presidents claim authority to negotiate with foreign countries, ratify treaties approved by the Senate, interpret treaties’ terms outside the context of domestic litigation, and terminate the United States’ treaty commitments.⁴⁰ The Senate maintains its authority to provide (or withhold) consent to treaties proposed by the President, and it shapes treaties’ scope and meaning through its power to condition consent on reservations, understandings, and declarations.⁴¹ Congress also plays a role when it enacts legislation implementing treaties’ requirements into U.S. statutes.⁴² While unresolved questions about the treaty power have persisted since the Constitution was written, treaty-making remains a unique and dynamic part of American constitutional law and practice.