Figure A-1. Steps in the Making of a Treaty

Source: Reprinted from Congressional Research Service, Treaties and Other International Agreements: The Role of the United States Senate, A Study Prepared for the Senate Comm. on Foreign Relations 8-9 (Comm. Print 2001).

Figure A-2. Steps in the Making of an Executive Agreement

Source: Reprinted from Congressional Research Service, Treaties and Other International Agreements: The Role of the United States Senate, A Study Prepared for the Senate Comm. on Foreign Relations 8-9 (Comm. Print 2001).

Restatement (Third) of Foreign Relations, §101 (1987). Recorded international law dates back to agreements between Mesopotamian rulers five thousand years ago, but international law as we understand it began with the Roman Empire, whose scholars formulated a jus gentium (law of nations) they believed universally derivable through reason. See generally David J. Bederman, International Law in Antiquity (2001). The term "international law" appears to have been coined by Jeremy Bentham in 1789. Jeremy Bentham, An Introduction to the Principles of Morals and Legislation 326 n. 1 (Hafner Publ'g Co. 1948) (1789). Although originally governing State-to-State relations, the scope of international law has grown, beginning in the latter half of the 20^th century with the emerging fields of human rights law and international criminal law, to regulate the treatment and conduct of individuals in certain circumstances. See, e.g., Universal Declaration on Human Rights, UN GAOR, Supp. No. 16, UN Doc. A/6316 (1948); Geneva Convention (Third) Relative to the Treatment of Prisoners of War, Aug. 12, 1949, 6 U.S.T. 3316, 75 U.N.T.S. 135; Geneva Convention (Fourth) Relative to the Protection of Civilian Persons in Times of War, Aug. 12, 1949, 6 U.S.T. 3516, 75 U.N.T.S. 287; International Covenant on Civil and Political Rights, G.A. Res. 2200A, U.N. GAOR, 3^rd Comm., 21^st Sess., 1496^th plen. mtg., U.N. Doc. A/RES/2200A (XXI) (1966). See also U.S. State Dept. Pub. No. 3080, Report of Robert H. Jackson, International Conference on Military Trials 437 (1949) (arguing that crimes against humanity were "implicitly" in violation of international law even before the Nuremberg military trials of Nazi leadership for such offenses following World War II).

Restatement, supra footnote 1, §102.

See, e.g., Ware v. Hylton, 3 U.S. (3 Dall.) 199, 281 (1796) ("[w]hen the United States declared their independence, they were bound to receive the law of nations, in its modern state of purity and refinement"); Chisholm v. Georgia, 2 U.S. (2 Dall.) 419 (1793) ("the United States had, by taking a place among the nations of the earth, become amenable to the law of nations"); see also Letter from Thomas Jefferson, Secretary of State, to M. Genet, French Minister (June 5, 1793) (construing.¹¹⁴ The Supreme Court has deemed a provision non-self-executing when the text manifests an intent that the provision not be directly enforceable in U.S. courts¹¹⁵ or when the Senate conditions its advice and consent on the understanding that the provision is non-self-executing.¹¹⁶ Although the Supreme Court has not addressed the issue directly, many courts and commentators agree that provisions in international agreements that would require the United States to exercise authority that the Constitution assigns to Congress exclusively must be deemed non-self-executing, and implementing legislation is required to give such provisions domestic legal effect.¹¹⁷ Lower courts have concluded that, because Congress controls the power of the purse, a treaty provision that requires expenditure of funds must be treated as non-self-executing.¹¹⁸ Other lower courts have suggested that treaty provisions that purport to create criminal liability¹¹⁹ or raise revenue¹²⁰ must be deemed non-self-executing because those powers are the exclusive prerogative of Congress. Until implementing legislation is enacted, existing domestic law concerning a matter covered by a non-self-executing provision remains unchanged and controlling law in the United States.¹²¹ While it is clear that non-self-executing provisions in international agreements do not displace existing state or federal law, there is significant scholarly debate regarding the distinction between self-executing and non-self-executing provisions, including the ability of U.S. courts to apply and enforce them.¹²² Some scholars argue that, although non-self-executing provisions lack a private right of action, litigants can still invoke non-self-executive provisions defensively in criminal proceedings or when another source for a cause of action is available.¹²³ Other courts and commentators contend that non-self-executing provisions do not create any judicially enforceable rights, or that that they lack any status whatsoever in domestic law.¹²⁴ At present, the precise status of non-self-executing treaties in domestic law remains unresolved.¹²⁵ Despite the complexities of the self-execution doctrine in domestic, treaties and other international agreements operate in dual international and domestic law contexts.¹²⁶ In the international context, international agreements traditionally constitute binding compacts between sovereign nations, and they create rights and obligations that nations owe to one another under international law.¹²⁷ But international law generally allows each individual nation to decide how to implement its treaty commitments into its own domestic legal system.¹²⁸ The self-execution doctrine concerns how a treaty provision is implemented in U.S. domestic law, but it does not affect the United States' obligation to comply with the provision under international law.¹²⁹ When a treaty is ratified or an executive agreement concluded, the United States acquires obligations under international regardless of self-execution, and it may be in default of the obligations unless implementing legislation is enacted.¹³⁰ Congressional Implementation of International Agreements When an international agreement requires implementing legislation or appropriation of funds to carry out the United States' obligations, the task of providing that legislation falls to Congress.¹³¹ 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 provisions into domestic law.¹³² But the issue has not been resolved in any definitive way as it has not been addressed in a judicial opinion and continues to be the subject of debate occasionally.¹³³

By contrast, the Supreme Court has addressed the scope of Congress's power to enact legislation implementing non-self-executing treaty provisions. In a 1920 case, Missouri v. Holland,¹³⁴ the Supreme Court addressed 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.¹³⁵ 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.¹³⁶ But the Holland Court concluded that, even if those district court decisions were correct, their reasoning no longer applied once the United States concluded a valid migratory bird treaty.¹³⁷ In an opinion authored by Justice Holmes, the Holland Court concluded that the treaty power can be used to regulate matters that the Tenth Amendment otherwise might reserve to the states.¹³⁸ And if the treaty itself is constitutional, the Holland Court held, Congress has the power under the Necessary and Proper Clause¹³⁹ to enact legislation implementing the treaty into the domestic law of the United States without restraint by the Tenth Amendment.¹⁴⁰

Commentators and jurists have called some aspects of the Justice Holmes's reasoning in Holland into question,¹⁴¹ and some scholars have argued that the opinion does not apply to executive agreements.¹⁴² But the Supreme Court has not overturned Holland's holding related to Congress's power to implement treaties.¹⁴³ Nevertheless, principles of federalism embodied in the Tenth Amendment continue to impact constitutional challenges to U.S. treaties and their implementing statutes, including in the 2014 Supreme Court decision, Bond v. United States.¹⁴⁴

Bond concerned a criminal prosecution arising from a case of "romantic jealously" when a jilted spouse spread toxic chemicals on the mailbox of a woman with whom her husband had an affair.¹⁴⁵ Although the victim only suffered a "minor thumb burn," the United States brought criminal charges under the Chemical Weapons Convention Act of 1998—a federal statute that implemented a multilateral treaty prohibiting the use of chemical weapons.¹⁴⁶ 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.¹⁴⁷

Sometimes, a treaty or executive agreement will conflict with one of the three main tiers of domestic law—U.S. state law, federal law, or the Constitution. For domestic purposes, a ratified, self-executing treaty is the law of the land equal to federal law¹⁵³ and superior to U.S. state law,¹⁵⁴ but inferior to the Constitution.¹⁵⁵ A self-executing executive agreement is likely superior to U.S. state law,¹⁵⁶ but sole executive agreements may be inferior to conflicting federal law in certain circumstances (congressional-executive agreements or executive agreements pursuant to treaties are equivalent to federal law),¹⁵⁷ and all executive agreements are inferior to the Constitution.¹⁵⁸ In cases where ratified treaties or certain executive agreements are equivalent to federal law, the "last-in-time" rule establishes that a more recent federal statute will prevail over an earlier, inconsistent international agreement, while a more recent self-executing agreement will prevail over an earlier, inconsistent federal statute.¹⁵⁹

Treaties and executive agreements that are not self-executing, on the other hand, have generally been understood not to displace existing state or federal law in the absence of implementing legislation.¹⁶⁰ "The responsibility for transforming an international obligation arising from a non-self-executing treaty into domestic law falls to Congress."¹⁶¹ Accordingly, it appears unlikely that a non-self-executing agreement could be converted into judicially enforceable domestic law absent legislative action through the bicameral process.¹⁶²

The executive branch frequently is responsible for interpreting international agreements outside the context of domestic litigation.¹⁷² While the Supreme Court has final authority to interpret an agreement for purposes of applying it as domestic law in the United States, some questions of interpretation may involve exercise of presidential discretion or otherwise may be deemed "political questions" more appropriately resolved in the political branches. In Charlton v. Kelly, for example, the Supreme Court declined to decide whether Italy violated its extradition treaty with the United States, reasoning that, even if a violation occurred, the President "elected to waive any right" to respond to the breach by voiding the treaty.¹⁷³ Moreover, the executive branch often is well-positioned to interpret an agreement's terms given its leading role in negotiating agreements and its understanding of other nations' post-ratification practices.¹⁷⁴ Thus, even when a question of interpretation is to be resolved by the judicial branch, the Supreme Court has stated that the executive branch's views are entitled to "great weight"¹⁷⁵—although the Court has not adopted the executive branch's interpretation in every case.¹⁷⁶

Congress also possesses power to interpret international agreements by virtue of its power to pass implementing or other related legislation.¹⁷⁷ And because the Constitution expressly divides the treaty-making power between the Senate and the President, the Supreme Court has examined sources that reflect these entities' shared understanding of a treaty at the time of ratification.¹⁷⁸ The Senate's ability to influence treaty interpretation directly, however, may be limited to its role in the advice and consent process.¹⁷⁹ The Senate may, and frequently does, condition its consent on a requirement that the United States interpret a treaty in a particular fashion.¹⁸⁰ But after the Senate provides its consent and the President ratifies a treaty, resolutions passed by the Senate that purport to interpret the treaty are "without legal significance" according to the Supreme Court.¹⁸¹

The Constitution sets forth a definite procedure whereby the President has the power to make treaties with the advice and consent of the Senate, ¹⁸² but it is silent as to how to terminate them.¹⁸³ Although the Supreme Court has recognized directly the President's power to conclude certain executive agreements,¹⁸⁴ it has not addressed presidential power to terminate those agreements. The following section discusses historical practice and jurisprudence related to the withdrawal from and termination of international agreements.¹⁸⁵

Congress also has asserted the authority to direct the President to terminate congressional-executive agreements. For example, in the Comprehensive Anti-Apartheid Act of 1986, which was passed over President Reagan's veto, Congress instructed the Secretary of State to terminate an air services agreement with South Africa.¹⁹² And in the Trade Agreements Extension Act of 1951, Congress directed the President to "take such action as is necessary to suspend, withdraw or prevent the application of" trade concessions contained in prior trade agreements regulating imports from the Soviet Union and "any nation or area dominated or controlled by the foreign government or foreign organization controlling the world Communist movement."¹⁹³

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 Senate's advice and consent. Moreover, whereas an enacted federal statute can only be rescinded by a subsequent act of Congress, some argue that, just as the President has some unilateral authority to remove executive officers who were appointed with senatorial consent, the President may unilaterally terminate treaties made with the Senate's advice and consent.²⁰⁰

At the turn of the 20th century, government practice began to change, and a new form of treaty termination emerged: unilateral termination by the President without approval by the legislative branch. During the Franklin Roosevelt Administration and World War II, unilateral presidential termination increased markedly.²¹¹ Although Congress occasionally enacted legislation authorizing or instructing the President to terminate treaties during the 20th century,²¹² unilateral presidential termination became the norm.²¹³

The president's exercise of treaty termination authority did not generate 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. Carter²¹⁴ seeking to prevent President Carter from terminating a mutual defense treaty with the government of Taiwan²¹⁵ as part of the United States' recognition of the government of mainland China.²¹⁶ 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.²¹⁷ 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.²¹⁸ This four-Justice opinion, written by Justice 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 Reagan²¹⁹ and President George W. Bush.²²⁰

Customary international law is defined as resulting from "a general and consistent practice of States followed by them from a sense of legal obligation."²²¹ This means that all, or nearly all, nations consistently follow the practice in question and they must do so because they believe themselves legally bound, a concept often referred to as opinio juris sive necitatis (opinio juris).²²² If nations generally follow a particular practice but do not feel bound by it, it does not constitute customary international law.²²³ Further, there are ways for nations to avoid being subject to customary international law. First, a nation that is a persistent objector to a particular requirement of customary international law is exempt from it.²²⁴ Second, under American law, the United States can exempt itself from customary international law requirements by passing a contradictory statute under the "last-in-time" rule.²²⁵ As a result, the impact of customary international law that conflicts with other domestic law appears limited.

In examining nations' behavior to determine whether opinio juris is present, courts might look to a variety of sources, including, inter alia, relevant treaties, unanimous or near-unanimous declarations by the United Nations General Assembly concerning international law,²²⁶ and whether noncompliance with an espoused universal rule is treated as a breach of that rule.²²⁷ Uncertainties and debate frequently arise concerning how customary international law is defined and how firmly established a particular norm must be in order to become binding.²²⁸

Some particularly prevalent rules of customary international law can acquire the status of jus cogens norms—peremptory rules which permit no derogation, such as the international prohibition against slavery or genocide.²²⁹ For a particular area of customary international law to constitute a jus cogens norm, State practice must be extensive and virtually uniform.²³⁰

In a landmark 1938 decision, Erie Railroad Co. v. Tompkins, the Supreme Court rejected the then-longstanding notion that there was a "transcendental body of law" known as the general common law, which federal courts are permitted to identify and describe in the absence of a conflicting statute.²³⁴ Erie held that the "law in the sense in which courts speak of it today does not exist without some definite authority behind it" in the form of a state or federal statute or constitutional provision.²³⁵ Some jurists and commentators have argued that, because judicial application of customary international law requires courts to rely on the same processes used in discerning and applying the general common law, Erie should be interpreted to foreclose application of customary international law in U.S. courts.²³⁶ Many commentators, however, disagree with this view.²³⁷ Although the Supreme Court has not passed directly on the issue, in 1964, it discussed with approval a law review article in which then-professor and later judge of the International Court of Justice Philip C. Jessup argued that it would be "unsound" and "unwise" to interpret Erie to bar federal courts' application of customary international law.²³⁸ And in a 2004 case, the High Court rejected the view that federal courts have lost "all capacity" to recognize enforceable customary international norms as a result of Erie.²³⁹ Consequently, at present, the precise status of customary international law in the U.S. legal system remains the subject of debate. ²⁴⁰

While there is some uncertainty concerning the customary international law's role in domestic law, the debate has largely focused on circumstances in which customary international law does not conflict with an existing federal statute. When a federal statute does conflict with customary international law, lower courts consistently have concluded that the statute prevails.²⁴¹ And there do not appear to be any cases in which a court has struck down a federal statute on the ground that it violates customary international law.²⁴² Further, the Supreme Court's pre-Erie jurisprudence could be read to support the view that federal statutes prevail over customary international law. In The Paquete Habana, the Court explained that customary international law may be incorporated into domestic law, but only to the extent that "there is no treaty, and no controlling executive or legislative act or judicial decision" in conflict.²⁴³

While it appears that federal statutes will generally prevail over conflicting custom-based international law, customary international law can potentially affect how courts construe domestic law. Under the canon of statutory construction known as the Charming Betsy canon, when two constructions of an ambiguous statute are possible, one of which is consistent with international legal obligations and one of which is not, courts will often construe the statute so as not to violate international law, presuming such a statutory reading is reasonable.²⁴⁴

Filártiga was a highly influential decision that caused the ATS to "skyrocket" into prominence as a vehicle for asserting civil claims in U.S. federal courts for human rights violations even when the events underlying the claims occurred outside the United States.²⁵¹ But the expansion of the claims grounded in the ATS was not long-lived. Beginning with a 2004 decision, Sosa v. Alvarez-Machain, the Supreme Court began to place outer limits on the statute's application.²⁵² Sosa held that not all violations of international norms are actionable under the ATS—only those that "rest on a norm of international character accepted by the civilized world" and are defined with sufficient clarity and particularity.²⁵³ And even when a claim meets these standards, Sosa explained that federal courts must exercise "great caution" before deeming a claim actionable.²⁵⁴

Nine years later, in Kiobel v. Royal Dutch Petroleum Co., the Supreme Court further limited the ATS's reach by holding that courts should apply the canon of construction known as the presumption against extraterritoriality to the statute.²⁵⁵ Under Kiobel, foreign plaintiffs cannot sue foreign defendants in ATS suits when the relevant conduct occurred overseas.²⁵⁶ And in Jesner v. Arab Bank, PLC, a 2018 decision, the High Court concluded that foreign corporations are not subject to the liability under the ATS.²⁵⁷ Although the ATS remains a clear example of a U.S. statute incorporating customary international law, the Supreme Court's narrowing of ATS jurisdiction in Sosa, Kiobel, and Jesner has caused some commentators to question its continued relevance.²⁵⁸

Although the United States has long understood international legal commitments to be binding both internationally and domestically, the relationship between international law and the U.S. legal system implicates complex legal dynamics. In some areas, courts have established settled rules. For example, courts clearly have recognized that the Constitution permits the United States to make binding international commitments through both treaties and executive agreements.²⁵⁹ And the Supreme Court has held that only self-executing international agreements have the status of judicially enforceable domestic law.²⁶⁰ But other issues concerning the status of international law in the U.S. legal system have never been fully resolved.²⁶¹ The scope of presidential power to make executive agreements, the role of non-self-executing agreements and customary international law, and the division of power to withdraw from international agreements—like many international-law-related issues—have long been the subject of debate. Because the legislative branch possesses significant powers to shape and define the United States' international obligations, Congress is likely to continue to play a critical role in dictating the outcome of these debates in the future.

Source: Reprinted from Treaties and Other International Agreements: The Role of the United States Senate, A Study Prepared for the Senate Comm. on Foreign Relations, S. Rep. 106-9, at 8-9 (Comm. Print 2001).

Source: Reprinted from Treaties and Other International Agreements: The Role of the United States Senate, A Study Prepared for the Senate Comm. on Foreign Relations, S. Rep. 106-9, at 8-9 (Comm. Print 2001).

Restatement (Third) of Foreign Relations law of the United States, § 101 (1987) [hereinafter Third Restatement]. Recorded international law dates back to agreements between Mesopotamian rulers five thousand years ago, but international law as it now commonly understood began with the Roman Empire, whose scholars formulated a jus gentium (law of nations) they believed universally derivable through reason. See generally David J. Bederman, International Law in Antiquity (2001). Although originally governing nation-to-nation relations, the scope of international law has grown, beginning in the latter half of the 20th century with the emerging fields of human rights law and international criminal law, to regulate the treatment and conduct of individuals in certain circumstances. See, e.g., Universal Declaration on Human Rights, UN GAOR, Supp. No. 16, UN Doc. A/6316 (1948); Geneva Convention (Third) Relative to the Treatment of Prisoners of War, Aug. 12, 1949, 6 U.S.T. 3316, 75 U.N.T.S. 135; Geneva Convention (Fourth) Relative to the Protection of Civilian Persons in Times of War, Aug. 12, 1949, 6 U.S.T. 3516, 75 U.N.T.S. 287; International Covenant on Civil and Political Rights, G.A. Res. 2200A, U.N. GAOR, 3rd Comm., 21st Sess., 1496th plen. mtg., U.N. Doc. A/RES/2200A (XXI) (1966). See also U.S. State Dept. Pub. No. 3080, Report of Robert H. Jackson, International Conference on Military Trials 437 (1949) (arguing that crimes against humanity were "implicitly" in violation of international law even before the Nuremberg military trials of Nazi leadership for such offenses following World War II).

See, e.g., Ware v. Hylton, 3 U.S. (3 Dall.) 199, 281 (1796) ("When the United States declared their independence, they were bound to receive the law of nations, in its modern state of purity and refinement."); Chisholm v. Georgia, 2 U.S. (2 Dall.) 419, 474 (1793) ("[T]he United States had, by taking a place among the nations of the earth, become amenable to the law of nations."); Letter from Thomas Jefferson, Secretary of State, to M. Genet, French Minister (June 5, 1793), https://founders.archives.gov/documents/Jefferson/01-26-02-0189 (describing the law of nations as an "integral part" of domestic law). See also infra notes 231-233 (citing statements by the judicial and executive branch concerning the application of international law into domestic law).

See infra § Effects of International Agreements on U.S. Law.

See infra § Forms of International Agreements.

See id.

U.S. Const. art. II, § 2, cl. 2 (providing that the President "shall have Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two-thirds of the Senators present concur").

See infra § Executive Agreements.

See, e.g., Foster v. Neilson, 27 U.S. (2 Pet.) 253, 314 (1828) (Marshall, C.J.) (finding that international agreements entered into by the United States are "to be regarded in courts of justice as equivalent to an act of the legislature, wherever it operates of itself, without the aid of any legislative provision. But when"[W]hen the terms of the stipulation import a contract, when either of the parties engages to perform a particular act, the [agreement] 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."), overruled on other grounds by United States v. Percheman, 32 (7 Pet.) U.S. 517 Pet. 51, 8 L.Ed. 604 (1833). Congressional Research Service, Treaties and Other International Agreements: The Role of the United States Senate, A Study Prepared for the Senate Comm. on Foreign Relations 4 (Comm. Print 2001); Restatement, supra footnote 1, §, S. Rep. 106-97, at 4 (Comm. Print 2001) [hereinafter Treaties and Other International Agreements]; Third Restatement, supra note 1, § 111(3).

See infra § Customary International Law.

The Paquete Habana, 175 U.S. 677, 700 (1900). See also, e.g., United States v. Yousef, 327 F.3d 56 (2^nd Cir. 2003); Galo-Garcia v. I.N.S., 86 F.3d 916 (9^th Cir. 1996) ("whereGalo-Garcia v. Immigration and Naturalization Service, 86 F.3d 916 (9th Cir. 1996) ("[W]here a controlling executive or legislative act .. . . exist[s], customary international law is inapplicable.") (citation omitted).

As used in this report, the term "pact" is a generic term intended to encompass non-binding commitments between nations and legally binding international agreements.

For further detail of various types of international commitments and their relationship with U.S. law, see Treaties and Other International Agreements, supra note 8, at 43-97; Curtis A. Bradley & Jack L. Goldsmith, Presidential Control Over International Law, 131 Harv. L. Rev. 1201, 1207-09 (2018).

Vienna Convention on the Law of Treaties, entered into force Jan. 27, 1980art. 2, signed by the United States Apr. 24, 1970, 1155 U.N.T.S. 331 [hereinafter "Vienna Convention"], art.2]. Although the United States has not ratified the Vienna Convention, it recognizes it as generally signifyingcourts and the executive branch generally regard it as reflecting customary international law on many matters. See, e.g., De Los Santos Mora v. New York, 524 F.3d 183, 196 n.19 (2d Cir. 2008) ("Although the United States has not ratified the Vienna Convention on the Law of Treaties, our Court relies upon it 'as an authoritative guide to the customary international law of treaties,' insofar as it reflects actual state practices." (quoting Avero Belg. Ins. v. Am. Airlines, Inc., 423 F.3d 73, 80 n.8 (2d Cir. 2005))); . See, e.g., Fujitsu Ltd. v. Federal Exp. Corp., 247 F.3d 423 (2^nd, 433 (2d Cir. 2001) ("we[W]e rely upon the Vienna Convention here as an 'authoritative guide to the customary international law of treaties ... [b]ecause the United States recognizes the Vienna Convention as a codification of customary international law ... and [it] acknowledges the Vienna Convention as, in large part, the authoritative guide to current treaty law and practice") (internal citations omitted).

The term "treaty" is not always interpreted under U.S. law to refer only to those agreements described in Article II, § 2 of the Constitution. See Weinberger v. Rossi, 456 U.S. 25, 31-32 (1982) (interpreting statute barring discrimination except where permitted by "treaty" to refer to both treaties and executive agreements); B. Altman & Co. v. United States, 224 U.S. 583, 601 (1912) (construing the term "treaty," as used in statute conferring appellate jurisdiction, to also refer to executive agreements).

Under international law, States that have signed but not ratified treaties have the obligation to refrain from acts that would defeat the object or purpose of the treaty. See Vienna Convention, art. 18.

A "reservation" is "a unilateral statement ... made by a State, when signing, ratifying, accepting, approving or acceding to a treaty, whereby it purports to exclude or to modify the legal effect of certain provisions of the treaty in their application to that State." Id. art.2(1)(d). In practiceThird Restatement, supra note 1, § 301(1);

See id. For more on variations of the definition of the term "treaty," see supra notes 13-14.

See infra § Executive Agreements.

See infra § Nonlegal Agreements.

See Third Restatement, supra note 1, § 301(1); Restatement (Fourth) of Foreign Relations Law of the United States: Treaties, Tentative Draft No. 1, § 101 cmt. a (Mar. 21, 2016) [hereinafter Fourth Restatement: Draft 1].

See Curtis A. Bradley, Unratified Treaties, Domestic Politics and the U.S. Constitution, 48 Harv. Int'l L.J. 307, 313 (2007) ("Under modern practice . . . consent is manifested through a subsequent act of ratification – the deposit of an instrument of ratification or accession with a treaty depositary in the case of multilateral treaties, and the exchange of instruments of ratification in the case of bilateral treaties."); Third Restatement, supra note 1, § 312 cmt. c ("A state can be bound upon signature, but that has now become unusual as regards important formal agreements.").

See supra note 6 (citing the Treaty Clause).

See, e.g., Louis Henkin, Foreign Affairs and the U.S. Constitution 177 (2d ed. 1996) ("As originally conceived, no doubt, the Senate was to be a kind of Presidential council, affording him advice throughout the treaty-making process and on all aspects of it . . . ."); Arthur Bestor, "Advice" from the Very Beginning, "Consent" When the End Is Achieved, 83 Am. J. Int'l L. 718, 726 (1989) ("[T]he use of the phrase 'advice and consent' to describe the relationship between the two partners clearly indicated that the Framers' conception was of a council-like body in direct and continuous consultation with the Executive on matters of foreign policy.").

See supra note 22.

On an occasion that has been described as the first and last time the President personally visited the Senate chamber to receive the Senate's advice on a treaty, President Washington went to the Senate in August 1789 to consult about proposed treaties with the Southern Indians. See 1 Annals of Cong. 65-71 (1789). But observers reported that he was so frustrated with the experience that he vowed never to appear in person to discuss a treaty again. See, e.g., William Maclay, Sketches of Debate in the First Senate of the United Sates 122-24 (George W. Harris ed. 1880) (record of the President's visit by Senator William Maclay of Pennsylvania); Ralston Hayden, The Senate and Treaties, 1789-1817, at 21-26 (1920) (providing a historical account of Washington's visit to the Senate).

See Memoirs of John Quincy Adams 427 (Charles Francis Adams ed., 1875) ("[E]ver since [President Washington's first visit to the Senate to seek its advice], treaties have been negotiated by the Executive before submitting them to the consideration of the Senate.").

See Zivotofsky v. Kerry, 135 S. Ct. 2076, 2086 (2015) ("The President has the sole power to negotiate treaties, . . . and the Senate may not conclude or ratify a treaty without Presidential action."); United States v. Curtiss-Wright Export Corp., 299 U.S. 304, 319 (1936) ("The President . . . makes treaties with the advice and consent of the Senate; but he alone negotiates.").

See Curtis A. Bradley & Jack L. Goldsmith, Treaties, Human Rights, and Conditional Consent, 149 U. Pa. L. Rev. 399, 405 (2000) ("The exercise of the conditional consent power has been in part a response by the Senate to its loss of any substantial 'advice' role in the treaty process."); Samuel B. Crandall, Treaties, Their Making and Enforcement 81 (2d ed. 1916) ("Not usually consulted as to the conduct of negotiations, the Senate has freely exercised its co-ordinate power in treaty making by means of amendments.").

Declarations are "statements expressing the Senate's position or opinion on matters relating to issues raised by the treaty rather than to specific provisions." Treaties and Other International Agreements, supra footnote 5note 8, at 11. See also Fourth Restatement: Draft 2, supra note 28, § 105 reporters' n.5.E ("The Senate sometimes uses 'declarations' to express views on matters of policy."). , at 11.

Understandings are "interpretive statements that clarify or elaborate provisions but do not alter them." Id.

Provisos concern "issues of U.S. law or procedure and are not intended to be included in the instruments of ratification to be deposited or exchanged with other countries." Id.

As a matter of customary international law, States are "obliged to refrain from acts which would defeat the object and purpose of a treaty," including entering reservations that are incompatible with a treaty's purposes. Vienna Convention, arts. 18-19.

See Fourth Restatement: Draft 2, supra note 28, § 105 reporters' n.3. See also United States v. Stuart, 489 U.S. 353, 374–75 (1989) (Scalia, J., concurring) ("[The Senate] may, in the form of a resolution, give its consent on the basis of conditions. If these are agreed to by the President and accepted by the other contracting parties, they become part of the treaty and of the law of the United States . . . .").

For discussion of historical examples of conditions attached by the Senate to treaties, see Fourth Restatement: Draft 2, supra note 28, § 105 reporters' n.5.

For example, in giving its advice and consent to the first treaty that was to be ratified by the United States after the adoption of the Constitution—dubbed the Jay Treaty because it was negotiated by the first Chief Supreme Court Justice of the United States, John Jay, who was appointed a special envoy to Great Britain despite his role in the judicial branch—the Senate insisted on suspending an article allowing Great Britain to restrict U.S. trade in the British West Indies. Senate Exec. Journal, 4th Cong., Special Sess., June 24, 1795, at 186. The Jay Treaty was ratified by Great Britain without objection to Senate's changes. See Hayden, supra note 24 at 86-88.

See, e.g., Curtis A. Bradley, International Law in the U.S. Legal System 36-39 (2d ed. 2015) (discussing scholarly debate over RUDs).

See, e.g., Louis Henkin, U.S. Ratification of Human Rights Treaties: The Ghost of Senator Bricker, 89 Am. J. Int'l L. 341, 343-44 (1995).

U.S. Const. art. 6, cl. 2 ("[A]ll Treaties made ... under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby....").

See (arguing that RUDs that aver that the United States is able to fully comply with its obligations under certain human rights treaties through existing domestic law render the treaties futile and are incompatible with their object and purpose); Fourth Restatement: Draft 2, supra note 28, § 105 cmt. 3 ("[R]eservations are more generally disallowed under international law if they are 'incompatible with the object and purpose of the treaty.'" (quoting Vienna Convention, supra note 13, art. 19(c))).

See Haver v. Yaker, 76 U.S. (9 Wall.) 32, 35 (1869) (noting that "the Senate are not required to adopt or reject [a treaty] as a whole, but may modify or amend it, as was done with the treaty under consideration").

See, e.g., Sosa v. Alvarez-Machain, 542 U.S. 692, 735 (2004) (reasoning that the International Covenant on Civil and Political Rights (ICCPR) could not form the basis for a claim because it was ratified "on the express understanding that it was not self-executing and so did not itself create obligations enforceable in the federal courts"); Oxygene v. Lynch, 813 F.3d 541, 546 (4th Cir. 2016) (interpreting a Senate understanding attached to its resolution of advice and consent to the Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment (CAT) and stating the that understanding "reflects the intent of the United States to influence how executive and judicial bodies later interpret the treaty on both the international and domestic level"); Pierre v. Gonzales, 502 F.3d 109, 115 (2d Cir. 2007) ("The definition of torture under domestic immigration law, and the scope of an individual's entitlement to CAT relief, is therefore governed by the text of the CAT subject to the terms of the Senate ratification resolution."); Buell v. Mitchell, 274 F.3d 337, 372 (6th Cir. 2001) (rejecting petitioner's claim that Ohio's death penalty violates international law in part by noting U.S. reservations to relevant treaties).

See Halberstam, supra footnote 17, at 602; Damrosch, supra footnote 17, at 527; Vázquez, supra footnote 17, at 609 (concluding, however, that "the treatymakers do have the power under our Constitution to render treaties non-self-executing by attaching declarations of non-self-execution").

Curtis A. Bradley and Jack L. Goldsmith, Treaties, Human Rights, and Conditional Consent, 149 U. Pa. L. Rev. 399, 446 (2005).

See, e.g., Pierre v. Gonzales, 502 F.3d 109, 115 (2d Cir. 2007) ("The definition of torture under domestic immigration law, and the scope of an individual's entitlement to ... relief [under the United Nations Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment (CAT)], is therefore governed by the text of the CAT subject to the terms of the Senate ratification resolution."); Buell v. Mitchell, 274 F.3d 337, 372 (6^th Cir. 2001) (rejecting petitioner's claim that Ohio's death penalty violates international law in part by noting U.S. reservations to relevant treaties); Beazley v. Johnson, 242 F.3d 248, 264 (5^th Cir. 2001) (suggesting Senate's reservation to provision of ICCPR prohibiting imposition of death sentence for defendants less than 18 years of age was valid).

See Sosa v. Alvarez-Machain, 542 U.S. 692, 735 (2004) (holding the International Covenant on Civil and Political Rights (ICCPR) could not form basis for international law claim because it was ratified "on the express understanding that it was not self-executing and so did not itself create obligations enforceable in the federal courts"). See also Guaylupo-Moya v. Gonzales, 423 F.3d 121, 137 (2d Cir. 2005) ("Th[e declaration that the ICCPR is not self-executing] means that the provisions of the ICCPR do not create a private right of action or separate form of relief enforceable in United States courts."); United States v. Duarte-Acero, 296 F.3d 1277, 1283 (11^th11th Cir. 2002) (noting that the "ICCPR does not create judicially-enforceable individual rights" because of the U.S. reservation to the treaty declaring that Articles 1-27 are non-self-executing); United States ex rel. Perez v. Warden, 286 F.3d 1059, 1063 (8^th8th Cir. 2002) ("[T]he ICCPR does not bind federal courts because the treaty is not self-executing and Congress has yet to enact implementing legislation.").

See Oona A. Hathaway, et al., International Law at Home: Enforcing Treaties in U.S. Courts, 37 Yale J. Int'l L. 51, 76-77 (2012) (arguing treaties may be enforced indirectly, defensively, or as an interpretive guide). One commentator has urged courts to construe the non-self-executing declarations to prohibit only the creation of a private right of action, but to allow courts to apply treaties directly to provide a judicial remedy in other cases. See David Sloss, The Domestication of International Human Rights: Non-Self-Executing Declarations and Human Rights Treaties, 24 Yale J. Int'l L. 129 (1999).

See Hathaway et al., supra footnote 22, at 87-88.

See 1 U.S.C. §112b (requiring text of executive agreements to be transmitted to Congress within 60 days, subject to certain exceptions).

E.g., American Ins. Ass'n v. Garamendi, 539 U.S. 396, 415 (2003) ("our infra notes 44-46 (discussijng historical usage of executive agreements and related judicial opinions).

The Case-Zablocki Act of 1972, Pub. L. No. 92-403, 86 Stat. 619, requires that all "international agreements" other than treaties be transmitted to Congress within 60 days of their entry into force for the United States. 1 U.S.C. § 112b. The act does not define what sort of arrangements constitute "international agreements," though the legislative history suggests that Congress "did not want to be inundated with trivia . . . [but wished] to have transmitted all agreements of any significance." H.R. Rep. No. 92-1301(1972). Implementing State Department regulations establish criteria for assessing when a compact constitutes an "international agreement" that must be reported under the Case-Zablocki Act. These regulations provide that "[m]inor or trivial undertakings, even if couched in legal language and form," are not considered to fall under the purview of the act's reporting requirements. 22 C.F.R. § 181.2(a). Similarly, although federal law generally requires the State Department publish all international agreements to which the United States is a party, an exception is made which affords the Secretary of State discretion to decline to publish some executive agreements when "public interest in such agreements is insufficient to justify their publication." 1 U.S.C. § 112a(b).

State Department, Office of Treaty Affairs, Texts of International Agreements to which the US is a Party (TIAS), at http://www.state.gov/s/l/treaty/tias/index.htm.

This estimate is based on multiple sources which rely on data provided by the State Department, including Treaties and Other International Agreements, supra footnote 5, at 39 (providing numbers from 1789 through 1999) and William R. Slomanson, Fundamental Perspectives on International Law 376 (5^th ed. 2007) (discussing published executive agreements and treaties concluded between 1789 and 2004). Data from 2005 onward was collected from the State Department's TIAS website, supra footnote 26 (concerning executive agreements reported to Congress), along with the State Department's website identifying agreements reported to Congress pursuant to the Case-Zablocki Act, at http://www.state.gov/s/l/treaty/caseact/, as well as the Legislative Information System database (identifying treaties submitted to the U.S. Senate for consideration).

The Case-Zablocki Act of 1972 (P.L. 92-403) requires that all "international agreements" other than treaties be transmitted to Congress within 60 days of their entry into force for the United States. The act does not define what sort of arrangements constitute "international agreements," though the legislative history suggests that Congress "did not want to be inundated with trivia ... [but wished] to have transmitted all agreements of any significance." H.Rept. 92-1301, 92^nd Cong. (1972). Implementing State Department regulations establish criteria for assessing when a compact constitutes an "international agreement" that must be reported under the Case-Zablocki Act. These regulations provide that "[m]inor or trivial undertakings, even if couched in legal language and form," are not considered to fall under the purview of the act's reporting requirements. 22 C.F.R. §181.2(a). Similarly, although federal law generally requires the State Department to publish all international agreements to which the United States is a party, an exception is made which affords the Secretary of State the discretion to decline to publish some executive agreements when "public interest in such agreements is insufficient to justify their publication." 1 U.S.C. §112a(b).

In a 1953 congressional hearing, Secretary of State John Foster Dulles was asked how many executive agreements had been entered by the United States pursuant to the NATO Treaty. Dulles replied, with some degree of hyperbole, "about 10,000.... Every time we open a new privy, we have an executive agreement." Hearing on S.J. Res. 1 and S.J. Res. 43: Before a Subcommittee of the Senate Judiciary Committee, 83^rd Cong., 1^st Sess. (1953), 877.

Treaties and Other International Agreements, supra footnote 5, at 5. See also CRS Report 97-896, Why Certain Trade Agreements Are Approved as Congressional-Executive Agreements Rather Than Treaties, by [author name scrubbed], [author name scrubbed], and [author name scrubbed]; Louis Henkin, Foreign Affairs and the U.S. Constitution (2^nd ed. 1996) at 215-18.

Treaties and Other International Agreements, supra footnote 5, at 5.

Id.

U.S. Const. art. VI, §2 ("the laws of the United States ... [and] all treaties made, or which shall be made, under the authority of the United States, shall be the supreme Law of the Land").

See Treaties and Other International Agreements, supra footnote 5, at 5, citing U.S. Const. arts. II, §1 (executive power), §2 (commander in chief power, treaty power), §3 (receiving ambassadors). Courts have recognized foreign affairs as an area of very strong executive authority. See United States v. Curtiss-Wright Export Corp., 299 U.S. 304 (1936).

See Restatement, supra footnote 1, §303 (4). See also Zivotofsky v. Kerry, 135 S.Ct. 2076 (2015) (recognizing that the Constitution confers the President with exclusive authority to recognize foreign states and their territorial bounds, and striking down a statute that impermissibly interfered with the exercise of such authority).

See Dames & Moore v. Regan, 453 U.S. 654 (1981) (upholding sole executive agreement concerning the handling of Iranian assets in the United States, despite the existence of a potentially conflicting statute, given Congress's historical acquiescence to these types of agreements); Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579 (1952) ("When the President acts pursuant to an express or implied authorization of Congress, his powers are at their maximum.... Congressional inertia, indifference or quiescence may ... invite, measures of independent Presidential responsibility.... When the President takes measures incompatible with the expressed or implied will of Congress, his power is at its lowest ebb, for then he can rely only upon his own constitutional powers minus any constitutional powers of Congress over the matter") (Jackson, J., concurring). But see Medellin v. Texas, 552 U.S. 491, 531-532 (2008) (suggesting that Dames & Moore analysis regarding significance of congressional acquiescence might be relevant only to a "narrow set of circumstances," where presidential action is supported by a "particularly longstanding practice" of congressional acquiescence).

Compare Edwin Borchard, Treaties and Executive Agreements: A Reply, 54 Yale L. J. 616 (1945) (arguing that the congressional-executive agreement is not a constitutionally permissible alternative to a treaty, and that sole executive agreements are permissible in limited circumstances); Bradford C. Clark, Domesticating Sole Executive Agreements, 93 Va. L. Rev. 1573See, e.g., Garamendi, 539 U.S. at 415 (discussing "executive agreements to settle claims of American nationals against foreign governments" dating back to "as early as 1799"); Act of Feb. 20, 1792, § 26, 1 Stat. 239 (act passed by the Second Congress authorizing postal-related executive agreements).

See Treaties and Other International Agreements, supra note 8, at 38; Oona A. Hathaway, Treaties' End: The Past, Present, and Future of International Lawmaking in the United States, 117 Yale L.J. 1236, 1288 (2008); Bradley & Goldsmith, supra note 12, at 1210.

Bradley & Goldsmith, supra note 12, at 1213. See also Treaties and Other International Agreements, supra note 8, at 40.

See, e.g., CLOUD Act, Pub. L. No. 115-141, div. V, § 105 (codified at 18 U.S.C. § 2523) (authorizing data-sharing executive agreements with certain foreign nations); Foreign Assistance Act of 1961, Pub. Law No. 87-195 (codified as amended at 22 U.S.C. §§ 2151-2431k) (authorizing the President to furnish assistance to foreign nations "on such terms and conditions as he may determine, to any friendly country").

See Third Restatement, supra note 1, § 303(3); Treaties and Other International Agreements, supra note 8, at 86.

See Treaties and Other International Agreements, supra note 8, at 88. See also supra note 43 (citing Supreme Court case law recognizing the validity of sole executive agreements).

See Third Restatement, supra note 1, § 303(2); Henkin, supra note 22, at 217; Bradley & Goldsmith, supra note 12, at 1208.

See supra note 47 (citing examples of congressional-executive agreements).

See Treaties and Other International Agreements, supra note 8, at 5.

North American Free Trade Agreement, Dec. 17, 1992, Can.-Mex.-U.S., 32 I.L.M. 605 (entered into force Jan. 1, 1994).

See General Agreement on Tariffs and Trade, Oct. 30, 1947, 61 Stat. A3, 55 U.N.T.S. 187.

See Third Restatement, supra note 1, § 303(3) & cmt. f; Bradley & Goldsmith, supra note 12, at 1208; Treaties and Other International Agreements, supra note 8, at 86. See also Wilson v. Girard, 354 U.S. 524, 528-29 (1957) (giving effect to an executive agreement defining jurisdiction over U.S. forces in Japan that was concluded pursuant to a treaty).

Treaties and Other International Agreements, supra note 8, at 86-87 & n.117 (discussing examples in which Members of the Senate contended that certain executive agreements did fall within the purview of an existing treaty and required Senate approval).

U.S. Const. art. VI, § 2 ("[T]he laws of the United States . . . [and] all treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land . . . .").

See supra note 55.

See supra notes 43 & 49.

See Treaties and Other International Agreements, supra note 8, at 5 (citing U.S. Const. arts. II, § 1 (executive power), § 2 (commander in chief power, treaty power), § 3 (receiving ambassadors)).

Am. Ins. Ass'n v. Garamendi, 539 U.S. 396, 415 (2003); Dames & Moore v. Regan, 453 U.S. 654, 680 (1981); United States v. Pink, 315 U.S. 203, 229 (1942); United States v. Belmont, 301 U.S. 324, 330 (1937).

See Third Restatement, supra note 1, § 303 (4). See also Zivotofsky v. Kerry, 135 S.Ct. 2076, 2084-96 (2015) (recognizing that the Constitution confers the President with exclusive authority to recognize foreign states and their territorial bounds, and striking down a statute that impermissibly interfered with the exercise of such authority).

See Dames & Moore v. Regan, 453 U.S. 654, 686 (1981) (upholding sole executive agreement concerning the handling of Iranian assets in the United States, despite the existence of a potentially conflicting statute, given Congress's historical acquiescence to these types of agreements); Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579, 635-38 (1952) (Jackson, J., concurring) ("When the President acts pursuant to an express or implied authorization of Congress, his powers are at their maximum . . . . Congressional inertia, indifference or quiescence may . . . invite, measures of independent Presidential responsibility . . . . When the President takes measures incompatible with the expressed or implied will of Congress, his power is at its lowest ebb, for then he can rely only upon his own constitutional powers minus any constitutional powers of Congress over the matter."). But see Medellín v. Texas, 552 U.S. 491, 531-32 (2008) (suggesting that Dames & Moore analysis regarding significance of congressional acquiescence might be relevant only to a "narrow set of circumstances," where presidential action is supported by a "particularly longstanding practice" of congressional acquiescence).

See supra note 63.

See Treaties and Other International Agreements, supra note 8, at 88. See also United States v. Belmont, 301 U.S. 324, 330 (1937) (recognizing constitutional authority for the Litvinov Assignment); United States v. Pink, 315 U.S. 203, 229 (1942) (confirming the holding in Belmont).

See supra notes 47, 50-54.

See supra notes 48, 55-58.

See supra notes 60-65.

See Harold Hongju Koh, Triptych's End: A Better Framework to Evaluate 21st Century International Lawmaking, 126 Yale L.J. Forum 338, 345 (2017); Daniel Bodansky & Peter Spiro, Executive Agreements+, 49 Vand. J. Transnat'l L. 885, 887 (2016).

For example, the Obama Administration described the Paris Agreement on climate change as an executive agreement, and commentators discussed multiple possible sources of executive authority on which to conclude the Agreement, but the executive branch did not publicly articulate the precise sources of executive authority on which President relied in entering into the Paris Agreement. See CRS Report R44761, Withdrawal from International Agreements: Legal Framework, the Paris Agreement, and the Iran Nuclear Agreement, by [author name scrubbed], at 18 & n. 146-149. See also Bodansky & Spiro, supra note 69, at 908-914 (citing the Anti-Counterfeiting Trade Agreement, Minamata Convention on Mercury, and inter-governmental agreements related to reporting of foreign income as executive agreements that did not have a specific, identifiable source of statutory or constitutional authority, but that were concluded as a new form of executive agreement during the Obama Administration).

See Bodansky & Spiro, supra note 69, at 927; Koh, supra note 69, at 345-48.

See Bradley & Goldsmith, supra note 12, at 1263.

Compare Yoo, supra footnote 37note 73, at 821 ("Treaties .. . . remain the required instrument of national policy when the federal government reaches international agreements on matters outside of Article I, Section 8, or over which the President and Congress possess concurrent and potentially conflicting powers)."); with Hathaway, supra footnote 37note 45, at 1270-127171 (disagreeing with delineation argued by Yoo, supra, and arguing that "areas of law in which Article II treaties are used extensively, including human rights, dispute resolution, arms control, aviation, the environment, labor, consular relations, taxation, and telecommunications almost never extend beyond Congress's Article I powers ...").

Third Restatement, supra footnotenote 1, at §§ 302, n. 5; Seesee also Greater Tampa Chamber of Commerce v. Goldschmidt, 627 F.2d 258, 265-66 (D.C. Cir. 1980) (finding that plaintiffs lacked standing to challenge the propriety of the form taken by an international agreement between the United States and United Kingdom). Executive agreements dealing with matters having no direct impact upon private interests in the United States (e.g., agreements concerning military matters or foreign relations) are rarely the subject of domestic litigation, in part because persons typically cannot demonstrate that they have suffered an actual, redressable injury and therefore lack standing to challenge such agreements. Third Restatement, supra footnotenote 1, at §§ 303, n. 11.

See Made in the USA FoundationFound. v. United States, 242 F.3d 1300 (11^th, 1310-19 (11th Cir. 2001) (assessment of whether the North American Free Trade Agreement was properly entered as a congressional-executive agreement rather than a treaty was a non-justiciable political question), cert. denied by United Steelworkers of America, AFL-CIO, CLC v. United States, 534 U.S. 1039 (2001).

See Inter-American Treaty of Reciprocal Assistance, 62 Stat. 1681, entered into force December 3, 1948 Dec. 3, 1948, 62 Stat. 1681; North Atlantic Treaty, 63 Stat. 2241, entered into force August Aug. 24, 1949, 63 Stat. 2241; Security Treaty Between Australia, New Zealand and the United States of America, 3 U.S.T. 3420, entered into force April 29, 1952, 3 U.S.T. 3420; Mutual Defense Treaty Between the United States of America and the Republic of the Philippines, 3 U.S.T. 3947, U.S.-Phil., entered into force August Aug. 27, 1952, 3 U.S.T. 3947; Mutual Defense Treaty Between the United States of America and the Republic of Korea, 5 U.S.T. 2368, U.S.-Kor., entered into force November Nov. 17, 1954, 5 U.S.T. 2368; Southeast Asia Collective Defense Treaty, 6 U.S.T. 81, entered into force February Feb. 19, 1955, 6 U.S.T. 81; Treaty of Mutual Cooperation and Security Between the United States of America and Japan, 11 U.S.T. 1632, U.S.-Japan, entered into force June 23, 1960 11 U.S.T. 1632, (replacing Security Treaty Between the United States of America and Japan, 3 U.S.T. 3329, U.S.-Japan, entered into force April Apr. 28, 1952, 3 U.S.T. 3329).

See generally CRS Report 98-958, Extradition To and From the United States: Overview of the Law and RecentContemporary Treaties, by [author name scrubbed] and [author name scrubbed], at Appendix A (listing bilateral extradition treaties to which the United States is a party). Congress enacted statutes that permitted in certain circumstances the extradition of non-citizens to foreign countries even in the absence of a treaty, P.L.Pub. L. No. 104-132, Title IV, § 443(a) (1996), as well as the surrender of U.S. citizens to face prosecution before the International Tribunals for Rwanda and Yugoslavia, P.L. 104-106, Div. A, §Pub. L. No. 104-106, § 1342 (1996). The U.S. Court of Appeals for the Fifth Circuit upheld the legality of the latter statute, and held that extradition may be effectuated either pursuant to a treaty or authorizing statute. Ntakirutimana v. Reno, 184 F.3d 419 (5^th, 425 (5th Cir. 1999).

See, e.g., Convention on the Prevention and Punishment of the Crime of Genocide, entered into force for the United States on February Feb. 23, 1989, 78 U.N.T.S. 277; International Covenant on Civil and Political Rights, entered into force for the United States Sep. 8, 1992, S. Exec. Doc. E, 95^th95th Cong., 2^nd2nd. Sess., 99 U.N.T.S. 171, entered into force for the United States on September 8, 1992; Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, entered into force for the United States Nov. 20, 1994, S. Treaty Doc. No. 95-2, 1465 U.N.T.S. 85 , entered into force for the United States on November 20, 1994.

See, e.g., Treaty on the Non-Proliferation of Nuclear Weapons, 21 U.S.T. 483, entered into force March 5, 1970 Mar. 5, 1970, 21 U.S.T. 483; Treaty on the Limitation of Anti-Ballistic Missile Systems, United States and the Union of the Soviet Socialist Republics, 23 U.S.T. 3435, entered into force October 3, 1972U.S.-U.S.S.R., entered into force Oct. 3, 1972, 23 U.S.T. 3435; Convention on the Prohibition of Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction, entered into force April 29, 1997 S. Treaty Doc. No. 103-21, entered into force April 29, 1997. But see 22 U.S.C. § 2573 (provision of Arms Control and Disarmament Act of 1961, as amended, generally barring acts that oblige the United States to limit forces or armaments in a "military significant manner" unless done pursuant to a treaty or further affirmative legislation by Congress); Interim Agreement on Certain Measures with Respect to the Limitation of Strategic Offensive Arms, United States-Soviet Union, 23 U.S.T. 3462, entered into force October 3, 1972 Oct. 3, 1972, 23 U.S.T. 3462, (Strategic Arms Limitation Talks (SALT I) Interim Agreement which was entered as a congressional-executive agreement pursuant to P.LPub. L. No. 92-448, 86 Stat. 746, and was intended as a stop-gap, five-year measure while the parties negotiated a permanent agreement).

For a list of tax treaties to which the United States is a party, see IRS, United States Income Tax Treaties - A to Z, https://www.irs.gov/businesses/international-businesses/united-states-income-tax-treaties-a-to-z (last updated June 19, 2018).

See, e.g., International Convention for the Prevention of Pollution of the Sea by Oil, with Annexes, 12 U.S.T. 2989, 327 U.N.T.S. 3, entered into force for the United States on December 8, 1961; United Nations Framework Convention on Climate Change, with Annexes, Sen. Treaty Doc. 102-38, 1771 UNTS 107, entered into force March 21, 1994; Montreal Protocol on Substances that Deplete the Ozone Layer, with Annexes, SEN. TREATY DOC. 100-10, 1522 U.N.T.S. 3, entered into force January 1, 1989.

Under these agreements, parties generally agree to tax the income of residents of the other agreement parties at a reduced rate, or exempt those residents from taxation altogether. For a list of tax treaties to which the United States is a party, see International Revenue Service, United States Income Tax Treaties - A to Z, at http://www.irs.gov/Businesses/International-Businesses/United-States-Income-Tax-Treaties—A-to-Z.

See, e.g., Treaty Concerning the Canadian International Boundary, United States and United Kingdom, 35 Stat. 2003, entered into force June 4, 1908, 35 Stat. 2003; Treaty to Resolve Pending Boundary Differences and Maintain the Rio Grande and Colorado River as the International Boundary between the United States and Mexico, with Maps, 23 U.S.T. 371, U.S.-Mex., entered into force April Apr. 18, 1972, 23 U.S.T. 371. The executive branch has regularly entered agreements to "provisionally" set boundaries pending ratification of a treaty intended to permanently resolve a boundary dispute. While some of these provisional agreements have been for a short duration, others have remained in effect for many years on account of the failure to ratify alack of a ratified final agreement. For example, by way of a series of two-year executive agreements, the executive branch has continued to provisionally apply a proposed U.S.-Cuba maritime boundary agreement that was submitted to the Senate in 1978. See Sen. Exec. Doc. H, 96^th Cong., 1^st Sess.

Circular 175 initially referred to a 1955 Department of State Circular which established a process for the coordination and approval of international agreements. These procedures, as modified, are now found in 22 C.F.R. Part 181 and 11 Foreign Affairs Manual (F.A.M.) chapter 720.

11 F.A.M. § 723.3 (2006).

S.Res. 536, S. Rept. 95-1171, 95^th Cong. (1977 Res. 536, 95th Cong. (1977).

11 F.A.M. § 723.4(b)-(c).

11 F.A.M. § 723.3.

See generally Duncan B. Hollis and Joshua J. Newcomer, "Political" Commitments and the Constitution, 49 Va. J. Int'l L. 507 (2009) (discussing the origins and constitutional implications of the practice of making political commitments).

Id. at §723.4(c).

See Third Restatement, supra note 1, § 301 reporters' n. 2 ("[T]he political inducements to comply with such [nonbinding] agreements may be strong and the consequences of noncompliance serious.").

Temporary arrangements intended to avoid dispute pending the conclusion of a permanent legal agreement are sometimes referred to as modi vivendi arrangements, and can potentially be either legal or nonlegal in nature. For further discussion of U.S. historical practice with respect to modi vivendi agreements, see William Hays Simpson, Use of Modi Vivendi in Settlement of International Disputes, 11 Rocky Mntn. L. Rev. 89 (1938); W. Michael Reisman, Unratified Treaties and Other Unperfected Acts in International Law: Constitutional Functions, 35 Vand. J. Transnat'l L. 729 (2002).

See generally Memorandum from Robert E. Dalton, Asst. Legal Adviser for Treaty Affairs, International Documents of a Non-Legally Binding Character, State Department, Memorandum, March 18, 1994, available atU.S. Dep't of State 1-5 (Mar. 18, 1994), http://www.state.gov/documents/organization/65728.pdf (discussing U.S. and international practice with respect to nonlegal, political agreements); Duncan B. Hollis and Joshua J. Newcomer, "Political" Commitments and the Constitution, 49 Va. J. Int'l L. 507 (2009) (discussing U.S. political commitments made to foreign States and the constitutional implications of the practice).

22 C.F.R. §181.2(a)(1).

Conference on Security and Cooperation in Europe: Final Act, Aug. 1, 1975, 73 Dep't State Bull. 323 (1975) [hereinafter Helsinki Accords].

22 C.F.R. § 181.2(a)(1) ("In the absence of any provision in the arrangement with respect to governing law, it will be presumed to be governed by international law."). See also Hollis & Newcomer, supra note 89, at 525 ("To date, most (but not all) international lawyers favor a presumption of treaty making in lieu of creating political commitments.").

22 C.F.R. § 181.2(a)(1).

Id. See also State Department Office of the Legal Adviser, Guidance on Non-Binding Documents, at http://www.state.gov/s/l/treaty/guidance/.

See S.Rept, e.g., S. Rep. No. 91-129 (1969) (Senate Committee on Foreign Relations report in favor of the National Commitments Resolution, S. Res. 85, 91st Cong. (1969), criticizing the undertaking of "national commitments" by the Executive, either through international agreements or unilateral pledges to other countries, without congressional involvement) [hereinafter "Committee Report"].

S. Res. 85, 91st CongRes. 85, 91^st Congress, 1^st Sess. (1969).

Id. According to the committee report accompanying the Resolution, the motivation for the Resolution wasResolution arose from concern over the growing development of "constitutional imbalance" in matters of foreign relations, with Presidents frequently making significant foreign commitments on behalf of the United States without congressional action. Among other things, the report criticized a practice it described as "commitment by accretion," by which a "sense of binding commitment arises out of a series of executive declarations, no one of which in itself would be thought of as constituting a binding obligation. Simply repeating something often enough with regard to our relations with some particular country, we come to support that our honor is involved in an engagement no less solemn than a duly ratified treaty."

S.Rept. 91-129, at 26 S. Rep. No. 91-129 (1969).

See, , e.g., H.R. 4438, Executive Agreements Review Act, 94^th Cong., 1^st Sess. (proposing to establish legislative veto over executive agreements involving national commitments); S.Res. 24, Treaty Powers Resolution, 95^th Cong., 1^st Sess.e.g., Orkin v. Taylor, 487 F.3d 734, 739 (9th Cir. 2007) ("'Sense of the Congress' provisions are precatory provisions, which do not in themselves create individual rights or, for that matter, any enforceable law."). For additional background on "sense of" provisions, see CRS Report 98-825, "Sense of" Resolutions and Provisions, by [author name scrubbed], "Sense of" Resolutions and Provisions, by [author name scrubbed].

See supra note 42 (discussing statutory notification requirements for treaties and executive agreements).

See State Dept.Dep't, Office of the Legal Adviser, Circular 175 Procedure, at http://www.state.gov/s/l/treaty/c175/ ("The Circular 175 procedure does not apply to documents that are not binding under international law. Thus, statements of intent or documents of a political nature not intended to be legally binding are not covered by the Circular 175 procedure.").

The text of the JCPOA and attached annexes may be viewed at http://www.state.gov/e/eb/tfs/spi/iran/jcpoa/.

Pub. L. No. 114-17, 129 Stat. 201 (2015) (codified in 42 U.S.C. § 2011 note and id. § 2160e).

See JCPOA, supra note 108, at 6.

See Office of Legal Adviser, U.S. Dep't of State, Digest of United States Practice in International Law 2015, at 123 (Sally J. Cummins & David P. Stewart eds., 2002). Some argue that, although the JCPOA was originally nonbinding under international law, its provisions became binding when it was incorporated into a U.N. Security Council Resolution. For more discussion on the legal status of the JCPOA, see CRS Legal Sidebar LSB10134 supra note 108 and CRS Report R44761, supra note 70, at 23-24.

See JCPOA at 6 (providing in the introduction to the agreement's operative clauses that "Iran and [the other JCPOA parties] will take the following voluntary measures within the timeframe as detailed in this JCPOA and its Annexes"). See also CQ Congressional Transcripts, House Foreign Affairs Committee Holds Hearing on Iran Nuclear Deal, July 28, 2015 (in response to questioning concerning the form of the agreement, Secretary of State John Kerry described the JCPOA as a "political agreement," and indicated that a motivation behind the agreement taking this form was because U.S. negotiators were concerned that "it's become impossible" for a treaty to be approved by the U.S. Senate).

For a detailed description of the Iran Nuclear Agreement Review Act, including the temporal scope and effect of the framework for congressional review contained within the act, see CRS Report R44085, Procedures for Congressional Action in Relation to a Nuclear Agreement with Iran: In Brief, by [author name scrubbed] and [author name scrubbed].

See infra § Self-Executing vs. Non-Self-Executing Agreements.

P.L. 114-17, §2, codified at 42 USC §2160e (providing that if Congress either enacts a joint resolution of approval of the JCPOA, or fails to enact a joint resolution of disapproval within the specified time period, then the President is permitted to act "consistent with existing statutory requirements" to provide sanctions relief to Iran pursuant to the JCPOA).

See, e.g., Medellin, 552 U.S. at 505 n.2 (2008) ("What we mean by 'self-executing' is that the treaty has automatic domestic effect as federal law upon ratification."); Cook v. United States, 288 U.S. 102, 119 (1933) ("For in a strict sense the [t]reaty was self-executing, in that no legislation was necessary to authorize executive action pursuant to its provisions."); Foster v. Neilson, 27 (2 Pet.) U.S. 253, 2542 Pet. 253, 315, 7 L.Ed. 415 (1829) (Marshall, C.J.) (describing a treaty as "equivalent to an act of the legislature" when it "operates of itself without the aid of any legislative provision"), overruled on other grounds by United States v. Percheman, 32 (7 Pet.) U.S. 51 (1833)). 7 Pet. 51, 8 L.Ed. 604 (1833). See generally Restatement, supra footnote 1, §111 & cmt. h.

E.g., MedellinMedellín, 552 U.S. at 505511-12 ("In sum, while treaties may comprise international commitments .. . . they are not domestic law unless Congress has either enacted implementing statutes or the treaty itself conveys an intention that it be 'self-executing' and is ratified on these terms.") (internal citations and quotations omitted); Whitney v. Robertson, 124 U.S. 190, 194 (1888) ("When the [treaty] stipulations are not self-executing, they can only be enforced pursuant to legislation to carry them into effect, and such legislation is as much subject to modification and repeal by congress as legislation upon any other subject."). See generally Restatement, supra footnote 1, §111(4)(a) & cmt. h.

For example, in the case of the United Nations Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, G.A. Res. 39/46, Annex, 39 U.N. GAOR Supp. No. 51, U.N. Doc. A/39/51 (1984), the Senate gave advice and consent subject to a declaration that the treaty was not self-executing. U.S. Reservations, Declarations, and Understandings to the Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, 136 Cong. Rec. H.R. 1 (daily ed., Oct. 27, 1990). Congress has specified that neither World Trade Organization (WTO) agreements nor rulings made by the WTO Dispute Settlement Body pursuant to these agreements have direct legal effect under U.S. domestic law. See CRS Report RS22154, World Trade Organization (WTO) Decisions and Their Effect in U.S. Law, by [author name scrubbed], [author name scrubbed], and [author name scrubbed].

Restatement, supra footnote 1, §111(4)(a) & reporters' n. 5-6.

See, e.g., John H. Jackson, Status of Treaties in Domestic Legal Systems: A Policy Analysis, 86 Am. J. Int'l L. 310 (1992); Jordan J. Paust, Self-Executing Treaties, 82 Am. J. Int'l L. 760 (1988); Carlos Manuel Vázquez, Treaties as Law of the Land: The Supremacy Clause and the Judicial Enforcement of Treaties, 122 Harv. L. Rev. 599 (2008); John C. Yoo, Globalism and the Constitution: Treaties, Non-Self-Execution, and the Original Understanding, 99 Colum. L. Rev. 1955 (1999).

See Restatement, supra footnote 1, §111, cmt. h.

Missouri v. Holland, 252 U.S. 416 (1920).

Id. at 432. Since Holland, a number of federal statutes implementing treaty requirements have been recognized by reviewing courts as constitutionally permissible under the Necessary and Proper Clause. See, e.g., United States v. Bond, 681 F.3d 149 (3^rd Cir. 2012), cert. granted, 133 S. Ct. 978 (U.S., Jan. 18, 2013) (applying Holland and holding that the Chemical Weapons Convention Implementation Act of 1998, 18 U.S.C. §229, was a constitutionally valid exercise of Congress's power under the Necessary and Proper Clause to implement a treaty requirement); United States v. Ferreira, 275 F.3d 1020 (11^th Cir. 2001) (upholding Hostage Taking Act, 18 U.S.C. §1203, as necessary and proper to implement the International Convention Against the Taking of Hostages); United States v. Wang Kun Lue, 134 F.3d 79 (2^nd Cir. 1997) (same). See also United States v. Lara, 541 U.S. 193 (2004) (citing to the Indian Commerce Clause and Treaty Clause as providing Congress with power to legislate on Indian tribe issues, and stating that "treaties ... can authorize Congress to deal with matters with which otherwise Congress could not deal ...") (internal quotations omitted).

See Printz v. United States, 521 U.S. 898 (1997); New York v. United States, 505 U.S. 144 (1992). See generally Edward T. Swaine, Does Federalism Constrain the Treaty Power?, 103 Colum. L. Rev. 403 (2003). For criticism of the Supreme Court's decision in Missouri v. Holland, and arguments that the treaty power may not expand Congress's legislative power, see Nicholas Quinn Rosenkranz, Executing the Treaty Power, 118 Harv. L. Rev. 1867 (2005).

See, e.g., Medellín, 552 U.S. at 507-08 (holding that Article 94 of the U.N. Charter, which states that each member of the U.N. "undertakes to comply" with the decisions of the International Court of Justice (ICJ) did not render an ICJ decision self-executing in the sense that it overrode contradictory state law); Foster, 27 U.S. at 254 (concluding that a provision in a treaty between United States and Spain that purported to preserve prior Spanish lands grants was non-self-executing).

See, e.g., Sosa v. Alvarez-Machain, 542 U.S. 692, 735 (2004) ("[T]he United States ratified the ICCPR on the express understanding that it was not self-executing and so did not itself create obligations enforceable in the federal courts.").

See, e.g., Fourth Restatement: Draft 2, supra note 28, § 110(3) & cmt. c. See also 5 Annals of Congress 771 (1796) (resolution from the House of Representatives stating that "when a treaty stipulates regulations on any of the subjects submitted by the Constitution to the power of Congress, it must depend for its execution as to such stipulations on a law or laws to be passed by Congress ").

See Edwards v. Carter, 580 F.2d 1055, 1058 (D.C. Cir. 1978) (per curiam) ("[E]xpenditure of funds by the United States cannot be accomplished by self-executing treaty; implementing legislation appropriating such funds is indispensable."), cert. denied, 436 U.S. 907 (1978); The Over the Top, 5 F.2d 838, 845 (D. Conn. 1925) ("All treaties requiring payments of money have been followed by acts of Congress appropriating the amount. The treaties were the supreme law of the land, but they were ineffective to draw a dollar from the treasury."); Turner v. Am. Baptist Missionary Union, 24 F. Cas. 344, 345 (C.C.D. Mich. 1852) ("[M]oney cannot be appropriated by the treaty-making power. This results from the limitations of our government.").

See Hopson v. Kreps, 622 F.2d 1375, 1380 (9th Cir. 1980) ("Treaty regulations that penalize individuals . . . require domestic legislation before they are given any effect."); United States v. Postal, 589 F.2d 862, 877 (5th Cir. 1979) (noting that constitutional restrictions on the use of a self-executing treaty to withdraw money from the treasury would also "be the case with respect to criminal sanctions"), cert. denied, 444 U.S. 832 (1979).

See Edwards, 580 F.2d at 1058 ("[T]he constitutional mandate that 'all Bills for raising Revenue shall originate in the House of Representatives,' . . . appears, by reason of the restrictive language used, to prohibit the use of the treaty power to impose taxes . . . .") (quoting U.S. Const., art. I, § 7, cl. 1); Swearingen v. United States, 565 F. Supp. 1019, 1022 (D. Colo. 1983) ("[A] treaty which created an exemption from the taxation of income of United States citizens . . . would be in contravention of the exclusive constitutional authority of the House of Representatives to originate all bills for raising revenues.").

See, e.g., Medellín v. Texas, 552 U.S. 491, 503-04 (2008) (concluding that because an ICJ judgment was not binding on domestic courts, state law concerning procedural limitations on successive filings of petitions for habeas corpus applied).

See, e.g., United States v. Postal, 589 F.2d 862, 876 (5th Cir. 1979) ("The self-execution question is perhaps one of the most confounding in treaty law."), cert. denied, 44 U.S. 832 (1979); Oona A. Hathaway et al., International Law at Home: Enforcing Treaties in U.S. Courts, 37 Yale J. Int'l L. 51, 51-52 (2012) (describing the self-execution doctrine as "[o]ne of the great challenges for scholars, judges, and practitioners alike").

See, e.g., David Sloss, The Domestication of International Human Rights: Non-Self-Executing Declarations and Human Rights Treaties, 24 Yale J. Int'l L. 129, 197-216 (1999).

Compare, e.g., Auguste v. Ridge, 395 F.3d 123, 133 (3d Cir. 2005) ("Treaties that are not self-executing do not create judicially-enforceable rights unless they are first given effect by implementing legislation."); with ITC Ltd. v. Punchgini, Inc., 482 F.3d 161 n.21 (2d Cir. 2007) ("Non-self-executing treaties do not become effective as domestic law until implementing legislation is enacted."); and Renkel v. United States, 456 F.3d 640, 643 (6th Cir. 2006) ("'[N]on-self-executing' treaties do require domestic legislation to have the force of law.").

See Bradley, supra note 35, at 44 (summarizing the debate of the domestic status of non-self-executing treaties).

See, e.g., Medellín v. Texas, 552 U.S. 491, 504-06 (2008) (discussing the distinction between the binding effect of treaties under international law versus domestic law).

See id. at 504 ("This Court has long recognized the distinction between treaties that automatically have effect as domestic law, and those that—while they constitute international law commitments—do not by themselves function as binding federal law."); Head Money Cases (Edye v. Robertson), 112 U.S. 580, 598 (1884) ("A treaty is primarily a compact between independent nations . . . . But a treaty may also contain provisions which . . . partake of the nature of municipal law . . . .").

See Head Money Cases, 112 U.S. at 598 ("[A treaty] depends for the enforcement of its provisions on the interest and the honor of the governments which are parties to it."); Fourth Restatement: Draft 2, supra note 28, § 110 cmt. c ("It is ordinarily up to each nation to decide how to implement domestically its international obligations.").

See Medellín, 552 U.S. at 522-23 (explaining that, although an ICJ judgment did "not of its own force constitute binding federal law[,]" the judgment "create[d] an international law obligation" for the United States); Fourth Restatement: Draft 2, supra note 28, § 110(1) ("Whether a treaty provision is self-executing concerns how the provision is implemented domestically and does not affect the obligation of the United States to comply with it under international law.").

See Third Restatement, supra footnote 1, §111, cmt. h.

Whereas Alexander Hamilton argued that the House of Representatives was obligated to appropriate funds for the Jay Treaty, supra note 34, James Madison, then a Member of the House, and others disagreed. Compare Enclosure to Letter from Alexander Hamilton to George Washington (Mar. 29, 1796), in Papers of Alexander Hamilton 98 (Harold C. Syrett ed., 1974) ("[T]he house of representatives have no moral power to refuse the execution of a treaty, which is not contrary to the constitution, because it pledges the public faith, and have no legal power to refuse its execution because it is a law—until at least it ceases to be a law by a regular act of revocation of the competent authority."), with 5 Annals of Cong. 493-94 (1796) (statement of Rep. Madison) ("[T]his House, in its Legislative capacity, must exercise its reason; it must deliberate; for deliberation is implied in legislation. If it must carry all Treaties into effect, . . . it would be the mere instrument of the will of another department, and would have no will of its own."); 5 Annals of Cong. 771 (1796) (proposed resolution of Rep. Blount) ("[W]hen a Treaty stipulates regulations on any of the subjects submitted by the Constitution to the power of Congress, it must depend, for its execution, as to such stipulations, on a law or laws to be passed by Congress. And it is the Constitutional right and duty of the House of Representatives, in all such cases, to deliberate on the expediency or inexpediency of carrying such Treaty into effect . . . .").

See Henkin, supra note 22, at 205.

252 U.S. 416 (1920).

See Migratory Bird Treaty Act, 40 Stat. 755 (1918); Convention for the Protection of Migratory Birds, Aug. 16, 1916, art. VIII, U.S.-Gr. Brit., 39 Stat. 1702.

United States v. McCullagh, 221 F. 288, 295-96 (D. Kan. 1915); United States v. Shauver, 214 F. 154, 160 (E.D. Ark. 1914).

See Missouri v. Holland, 252 U.S. 416, 433 (1920).

See Holland, 252 U.S. at 433-34 (concluding that the "treaty in question does not contravene any prohibitory words to be found in the Constitution" and is not "forbidden by some invisible radiation from the general terms of the Tenth Amendment").

See U.S. Const., art. I, § 8.

See Holland, 252 U.S. at 432 ("If the treaty is valid there can be no dispute about the validity of the statute under Article 1, Section 8, as a necessary and proper means to execute the powers of the Government."). Accord Neely v. Henkel, 180 U.S. 109, 121 (1901) ("The power of Congress to make all laws necessary and proper . . . includes the power to enact such legislation as is appropriate to give efficacy to any stipulations which it is competent for the President by and with the advice and consent of the Senate to insert in a treaty with a foreign power.").

Bond v. United States, 133134 S. Ct. 978 (U.S., Jan. 18, 2013). The petitioner had been convicted under the Chemical Weapons Convention Implementation Act of 1998, 18 U.S.C. §229, for attempting to poison her husband's paramour with toxic chemicals. The petitioner argues that the act, as applied, intrudes upon matters falling under traditional state authority, and that Congress may not act beyond the scope of its enumerated powers to implement a treaty. See Bond v. United States, Petition for Writ of Certiorari, No. 12-158 (U.S. Aug. 1, 2012), available at http://sblog.s3.amazonaws.com/wp-content/uploads/2012/09/12-158-2012-08-01-Bond-Cert-Pet-Final.pdf.

18 U.S.C. §229.

For further discussion of the Bond ruling, see CRS Report R42968, Bond v. United States: Validity and Construction of the Federal Chemical Weapons Statute, by [author name scrubbed].

Bond v. United States, 134 S. Ct. 2077, 2087 (2014). In the aftermath of Bond, however, the Ninth Circuit rejected a constitutional challenge to the CWCIA, finding that it was "within the constitutional powers of the federal government under the Necessary and Proper Clause and the Treaty Power...." United States v. Fries, 781 F.3d 1137, 1148 (9^th Cir. 2015) (quoting and adopting reasoning of the Third Circuit Court of Appeals in Bond, 681 F. 3d. at 165).

Bradley, supra note 35, at 86.

See United States v. Lara, 541 U.S. 193, 201 (2004) ("[A]s Justice Holmes pointed out, treaties made pursuant to [the treaty] power can authorize Congress to deal with 'matters' with which otherwise 'Congress could not deal.'") (quoting Missouri v. Holland, 252 U.S. 416, 433 (1920)); Reid v. Covert, 354 U.S. 1, 18 (1957) (plurality opinion) ("To the extent that the United States can validly make treaties, the people and the States have delegated their power to the National Government and the Tenth Amendment is no barrier.").

134 S. Ct. 2077 (2014).

See id. at 2090-91.

Chemical Weapons Convention Act of 1998, Pub. L. No. 105-277, div. I, tit. II, § 201(a), 112 Stat. 2681, 2681-866 (codified in 18 U.S.C. §§ 229-229f); Convention on the Prohibition of the Development, Production, Stockpiling, and Use of Chemical Weapons and on Their Destruction, art. 1, entered into force Apr. 29, 1997, S. Treaty Doc. No. 103-21, 1974 U.N.T.S. 317.

Bond, 134 S. Ct. at 2086-87.

See id. at 2087. Justice Scalia and Justice Thomas criticized Holland and argued that the Supreme Court should depart from its interpretation of congressional power to enact legislation that is necessary and proper to implement treaties. See id. at 2102 (Scalia, J., concurring in the judgment) (joined by Thomas, J.).

See id. at 2089-90.

Id. at 2090.

See id. at 2089-90.

Accord William S. Dodge, Bond v. United States and Congress's Role in Implementing Treaties, 108 AJIL Unbound 86, 87 (2015) ("The central holding of Bond is that statutes implementing treaties are not exceptions to the rules of statutory interpretation that the Supreme Court has developed to protect federalism.").

See Whitney, 124 U.S. at 194 (1888) ("By the constitution, a treaty is placed on the same footing, and made of like obligation, with an act of legislation. Both are declared by that instrument to be the supreme law of the land, and no superior efficacy is given to either over the other.").

See U.S. Const., art. VI, § 2 ("the laws of the United States ... . . [and] all treaties made, or which shall be made, under the authority of the United States, shall be the supreme Law of the Land"); Ware v. Hylton, 3 U.S. (3 Dall.) 199, 237 (1796) ("laws[L]aws of any of the States, contrary to a treaty, shall be disregarded").

See Reid v. Covert, 354 U.S. 1 (1957) (Black, J., plural155. See Am. Ins. Ass'n v. Garamendi, 539 U.S. 396, 416-17 & n.9 (2003) (stating that the power of a treaty to preempt state law is "[s]ubject . . . to the Constitution's guarantees of individual rights"); Boos v. Barry, 485 U.S. 312, 324 (1988) ("It is well established that 'no agreement with a foreign nation can confer power on the Congress, or on any other branch of Government, which is free from the restraints of the Constitution.'" (quoting Reid v. Covert, 354 U.S. 1, 16 (1957) (plurality op.))); Reid 354 U.S. at 17 (plurality op.) ("It would be manifestly contrary to the objectives of those who created the Constitution, as well as those who were responsible for the Bill of Rights-let alone alien to our entire constitutional history and tradition-to construe [the Supremacy Clause] as permitting the United States to exercise power under an international agreement without observing constitutional prohibitions."); Asakura v. City of Seattle, 265 U.S. 332, 343 (1924) ("The treaty-making power of the United States . . . does not extend 'so far as to authorize what the Constitution forbids . . . .'" (quoting De Geofroy v. Riggs, 133 U.S. 258, 267 (1890))); Doe v. Braden, 57 U.S. 635, 657 (1853) ("The treaty is therefore a law made by the proper authority, and the courts of justice have no right to annul or disregard any of its provisions, unless they violate the Constitution of the United States."). See generally Restatement, supra footnote 1, §115.

See United States v. Belmont, 301 U.S. 324, 330 (1937) (holding that sole executive agreement concerning settlement of U.S.-Soviet claims provided federal government with authority to recover claims held in New York banks, despite existence of state laws that would generally bar their recovery); United States v. Pink, 315 U.S. 203, 229 (1942) (similarconfirming Belmont).

Executive agreements have been held to beCourts have deemed executive agreements inferior to conflicting federal law when the agreement concernsagreements concern matters expressly within the constitutional authority of Congress. See, e.g., United States v. Guy W. Capps, Inc., 204 F.2d 655 (4^th, 660-61 (4th Cir. 1953) (findingruling that executive agreement contravening provisions of import statute was unenforceable); Third Restatement, supra footnotenote 1, § 115 reporters' n.5. However, an executive agreement may trumpa self-executing executive agreement has the potential to prevail over pre-existing federal law if itthe agreement concerns an enumerated or inherent executive power under the Constitution, or if Congress has historically acquiesced to the President entering agreements in the relevant area. See Pink, 315 U.S. at 230 ("[a]llAll Constitutional acts of power, whether in the executive or in the judicial department, have as much legal validity and obligation as if they proceeded from the legislature") (quoting . . . ." (quoting The Federalist No. 64 (John Jay))); Dames & Moore, 453 U.S. at 654 (upholding sole executive agreement concerning the handling of Iranian assets in the United States, despite the existence of a potentially conflicting statute, given Congress's historical acquiescence to these types of agreements).

See generally Third Restatement, supra footnotenote 1, § 115.

Whitney, 124 U.S. at 194See, e.g., Cook v. United States, 288 U.S. 102, 118-19 (1933); Whitney v. Robertson, 124 U.S. 190, 194-95 (1888); The Cherokee Tobacco, 78 U.S. (11 Wall.) 616, 621 (1870).

In recent years, thereThere has been some disagreement as to the domestic legal effect of a non-self-executing treaty following the enactment of implementing legislation. The weight of scholarly and judicial opinion arguably supports the view that it is only the implementing legislation, and not the underlying non-self-executing agreement, which has domestic legal effect. See, e.g., Stephens v. American Intern. Ins. Co., 66 F.3d 41, 45 (2d. Cir. 1995) (stating that legislation implementing non-self-executing agreement informed analysis as to whether state law was preempted, rather than the agreement itself); Safety Nat. Cas. Corp. v. Certain Underwriters Atat Lloyd's, London, 587 F.3d 714, 744 (5^th5th Cir. 2009) (Elrod, J., dissenting) (citing Supreme Court and appellate court decisions and scholarly writings to support view that only the legislation implementing a non-self-executing agreement is domestically enforceable, but not the agreement itself); Sloss, supra footnote 22note 123, at 149 ("[T]o the best of the author's knowledge, no U.S. court has ever held a treaty provision to be non-self-executing and then applied it directly to decide a case."); Restatement, supra footnote 1, §111 & cmt. h. ("[I]t is the implementing legislation, rather than the agreement itself, that is given effect as law in the United States. That is true even when a non-self-executing agreement is 'enacted' by, or incorporated in, implementing legislation."). However, at least one federal appellate court has recognized that a non-self-executing treaty itself becomes the "Law of the Land" under the Supremacy Clause upon the enactment of implementing legislation. Safety Nat. Cas. Corp., 587 F.3d at 714 (en banc) (also disputing dissent's claims that judicial and scholarly opinion supports a contrary view), cert. denied, LouisianaLa Safety Ass'n of Timbermen—Self Insurers Fund v. Certain Underwriters at Lloyd's, London, 131 S.Ct. 65562 U.S. 827 (2010).

MedellinMedellín v. Texas, 552 U.S. at 525-226.

Id. (holding that presidential memorandum ordering a U.S. state court to give effect to non-self-executing- treaty requirement did not constitute federal law preempting the state's procedural default rules). For further discussion, see CRS Report RL34450, Can the President Compel Domestic Enforcement of an International Tribunal's Judgment? Overview of Supreme Court Decision in Medellin v. Texas, by [author name scrubbed].

Restatement, supra footnote 1, §102(2).

See Sanchez-Llamas v. Oregon, 548 U.S. 331, 353–54 (2006) ("If treaties are to be given effect as federal law under our legal system, determining their meaning as a matter of federal law 'is emphatically the province and duty of the judicial department . . . .'" (quoting Marbury v. Madison, 5 U.S. 137, 177 (1803))).

See, e.g., BG Grp., PLC v. Republic of Argentina, 134 S. Ct. 1198, 1208 (2014); Lozano v. Montoya Alvarez, 134 S. Ct. 1224, 1232 (2014); Sumitomo Shoji Am., Inc. v. Avagliano, 457 U.S. 176, 183 (1982); Wright v. Henkel, 190 U.S. 40, 57 (1903).

Id. at §102 cmt. c.

See, e.g., Water Splash, Inc., 137 S. Ct. at 1511; Schlunk, 486 U.S. at 699. In one case, the Supreme Court changed its conclusion about the self-executing effect of a provision in an 1819 treaty with Spain after analyzing an authenticated Spanish-language version of the text. Compare Foster v. Neilson, 27 (2 Pet.) U.S. 253, 314-15 (1829) (construing English language version of 1819 treaty between the United States and Spain and deeming a provision stating that certain land grants "shall be ratified and confirmed" to be non-self-executing) (emphasis added), with United States v. Percheman, 32 U.S. (7 Pet.) 51, 88–89 (1833) (concluding that the land grant provision at issue was self-executing after interpreting the Spanish language version, which was translated to state that the land grants "shall remain ratified and confirmed") (emphasis added).

See, e.g., Abbott v. Abbott, 560 U.S. 1, 20 (2010); Sanchez-Llamas, 548 U.S. at 347; Société Nationale Industrielle Aerospatiale, 482 U.S. at 530; E. Airlines, Inc. v. Floyd, 499 U.S. 530, 552 (1991).

See, e.g., Water Splash, Inc., 137 S. Ct. at 1511; Medellín, 552 U.S. at 507; Air France, 470 U.S. at 400; Schlunk, 486 U.S. at 700.

See, e.g., Water Splash, Inc., 137 S. Ct. at 1511-12; Abbott, 560 U.S. at 16; Lozano v. Montoya Alvarez, 134 S. Ct. 1224, 1233 (2014); Air France, 470 U.S. at 404.

See, e.g., Medellín, 552 U.S. at 507; TWA v. Franklin Mint Corp., 466 U.S. 243, 259 (1984).

See Chan v. Korean Air Lines, Ltd., 490 U.S. 122, 134 (1989) ("We must thus be governed by the text-solemnly adopted by the governments of many separate nations-whatever conclusions might be drawn from the intricate drafting history that petitioners and the United States have brought to our attention. The latter may of course be consulted to elucidate a text that is ambiguous . . . . But where the text is clear, as it is here, we have no power to insert an amendment.").

See Relevance of Senate Ratification History to Treaty Interpretation, 11 U.S. Op. Off. Legal Counsel 28, 30 (1987) ("[T]he President is responsible for enforcing and executing international agreements, a responsibility that necessarily 'involves also the obligation and authority to interpret what the treaty requires.'" (quoting L. Henkin, Foreign Affairs and the Constitution 167 (1st ed. 1972))). Fourth Restatement: Draft 2, supra note 28, § 106 cmt. g ("Execution of a treaty requires interpretation, and the President often determines what a treaty means in the first instance . . . .").

See 229 U.S. 447, 475 (1913).

See Fourth Restatement: Draft 2, supra note 28, § 106 cmt. g & reporters' n.10 (discussing the executive branch's unique access to information related to treaty interpretation). Accord Sumitomo Shoji Am., Inc. v. Avagliano, 457 U.S. 176, 184-85 (1982) (giving deference to the Department of State's interpretation of a treaty because it is the agency "charged with [the treaty's] negotiation and enforcement").

See Water Splash, Inc. v. Menon, 137 S. Ct. 1504, 1512 (2017) (quoting Abbott v. Abbott, 560 U.S. 1, 15 (2010)); Medellín, 552 U.S. at 513; Sumitomo Shoji Am., Inc. v. Avagliano, 457 U.S. 176, 184–85 (1982); Kolovrat v. Oregon, 366 U.S. 187, 194 (1961).

See BG Grp., PLC v. Republic of Argentina, 134 S. Ct. 1198, 1208 (2014) (construing a dispute resolution provision in an investment treaty between the United Kingdom and Argentina and concluding "[w]e do not accept the Solicitor General's view as applied to the treaty before us"); Hamdan v. Rumsfeld, 548 U.S. 557, 629-30 (2006) (declining to adopt the executive branch's interpretation of Common Article 3 of the 1949 Geneva Conventions).

See Henkin, supra note 22, at 206 ("Congress, too, has occasion to interpret a treaty when it considers enacting implementing legislation, or other legislation to which the treaty might be relevant.").

See United States v. Stuart, 489 U.S. 353, 365-68 (1989) (considering, but deeming inconclusive, a treaty's ratification history); Société Nationale Industrielle Aerospatiale v. U.S. Dist. Court for S. Dist. of Iowa, 482 U.S. 522, 531 (1987) (discussing Secretary of State's analysis of the purposes of a treaty that was provided to the Senate).

See Fourteen Diamond Rings v. United States, 183 U.S. 176, 180 (1901) (declining to give legal weight to a Senate resolution attempting to clarify a ratified treaty because the "meaning of the treaty cannot be controlled by subsequent explanations of some of those who may have voted to ratify it.").

For example, the Senate frequently has conditioned its advice and consent to treaties on what has become known as the "Byrd-Biden condition," which provides that "the United States shall interpret the Treaty in accordance with the common understanding of the Treaty shared by the President and the Senate at the time the Senate gave its advice and consent to ratification . . . ." 134 Cong. Rec. 12849 (1988). See also Treaties and Other International Agreements, supra note 8, at 129-30 (providing a history of the Byrd-Biden condition and examples of its use).

See Fourteen Diamond Rings, 183 U.S. at 180 (describing a Senate resolution purporting to interpret an earlier, Senate-approved treaty as "absolutely without legal significance").

See supra note 6.

See, e.g., Goldwater v. Carter, 444 U.S. 996, 1003 (1979) (plurality opinion) ("[W]hile the Constitution is express as to the manner in which the Senate shall participate in the ratification of a treaty, it is silent as to that body's participation in the abrogation of a treaty."); Henkin, supra note 22, at 211 ("[T]he Constitution tells us only who can make treaties for the United States; it does not tell us who can unmake them.").

See supra § Executive Agreements.

For more detailed analysis of international and domestic legal principles related to withdrawal from international agreements, see CRS Report R44761, supra note 70.

See Bradley & Goldsmith, supra note 12, at 1225; Treaties and Other International Agreements, supra note 8 at 172; Third Restatement, supra note 1, § 339 reporters' n. 2.

See Bradley & Goldsmith, supra note 12, at 1225 ("Presidents clearly have the authority to terminate sole executive agreements and political commitments, since those agreements by Presidents based on their own constitutional authority."); Third Restatement, supra note 1, § 339 reporters' n. 2 ("No one has questioned the President's authority to terminate sole executive agreements.").

See, e.g., Julian Ku, President Rubio/Walker/Trump/Whomever Can Indeed Terminate the Iran Deal on "Day One," Opinio Juris (Sep. 10, 2015), https://tinyurl.com/ydfodbbo (arguing that, because the JCPOA is a nonbinding political commitment, the President can unilaterally terminate the arrangement); Ryan Harrington, A Remedy for Congressional Exclusion from Contemporary International Agreement Making, 118 W. Va. L. Rev. 1211, 1226 (2016) ("A political commitment also provides the executive branch with the ability to terminate the agreement unilaterally or to deviate from it without consequences.").

See Third Restatement, supra note 1, § 339 cmt. a; Treaties and Other International Agreements, supra note 8, at 174, 208; Michael J. Glennon, Can the President Do No Wrong?, 80 Am. J. Int'l L. 923, 926 (1986). See also Hathaway, supra note 45, at 1362 n.268 ("The President may withdraw from . . . a congressional-executive agreement unilaterally unless Congress has expressly limited the President's power to withdraw through . . . authorizing legislation . . . .").

See Third Restatement, supra note 1, § 339 cmt. a.

See id. For example, Section 125 of the Free Trade Act of 1974, which authorizes a fast-track process for consideration of legislation implementing free trade agreements, states: "Duties or other import restrictions required or appropriate to carry out any trade agreement entered into pursuant to this chapter . . . shall not be affected by any termination, in whole or in part, of such agreement or by the withdrawal of the United States from such agreement and shall remain in effect after the date of such termination or withdrawal for 1 year, unless" certain exceptions apply. 19 U.S.C. § 2135(e).

Pub. L. No. 99-440, § 306(b)(1), 313, 100 Stat. 1086, 1100 (1986) ("The Secretary of State shall terminate the Agreement Between the Government of the United States of America and the Government of the Union of South Africa Relating to Air Services Between their Respective Territories . . . ."), repealed by South African Democratic Transition Support Act of 1993, Pub. L. No. 103-149, § 4, 107 Stat. 1503, 1505. The Reagan Administration complied and provided the requisite notice of termination. See South African Airways v. Dole, 817 F.2d 119, 121 (D.C. Cir. 1987), cert denied, 484 U.S. 896 (1987).

See Pub. L. No. 82-50, § 5, 65 Stat. 72, 73 (1951). The Truman Administration relied on this law in terminating certain congressional-executive agreements with the Soviet Union and several Soviet satellite countries. Dep't of State, Office of the Historian, Foreign Relations of the United States, 1951, Europe: Political and Economic Developments, Volume IV, Part 2, https://history.state.gov/historicaldocuments/frus1951v04p2/d169.

See Curtis A. Bradley, Exiting Congressional-Executive Agreements, 67 Duke L.J. 1615, 1627-40 (2018); Michael Ramsey, Could President Trump Unilaterally Withdraw the U.S. from its International Agreements?, Originalism Blog (Sep. 29, 2016), https://tinyurl.com/yc26cfdr.

See Julian Ku & John Yoo, Trump Might be Stuck with NAFTA, L.A. Times (Nov. 29, 2016) (arguing that Congress's Commerce Clause authority bars the President from terminating the NAFTA without congressional authorization); Joel P. Trachtman, Trump Can't Withdraw from NAFTA Without a 'Yes' from Congress, The Hill (Aug. 16, 2017), https://tinyurl.com/y9byuyed ("If the president, acting alone, were to terminate U.S. participation in NAFTA, he would be imposing regulation on commerce, without congressional participation. This would be an unconstitutional usurpation of the powers granted to Congress.").

See Treaties and Other International Agreements, supra note 8, at 208 ("[T]he President's authority to terminate executive agreements . . . has not been seriously questioned in the past"); Bradley, supra note 194, at 1639 ("Congress has not indicated that it views congressional-executive agreements as special with respect to the issue of presidential termination authority.").

See, e.g., Barry M. Goldwater, Treaty Termination is a Shared Power, 65 A.B.A. J. 198, 199-200 (1979).

See, e.g., Clinton v. City of New York, 524 U.S. 417, 438 (1998) ("There is no provision in the Constitution that authorizes the President to enact, to amend, or to repeal statutes."); INS v. Chadha, 462 U.S. 919, 954 (1983) ("[R]epeal of statutes, no less than enactment, must conform with Art. I.").

See, e.g., David Gray Adler, The Constitution and the Termination of Treaties 89-110 (1986).

See, e.g., id. at 94.

Id. at §102, reporters' n. 2. The philosophy underlying the consistent objector exemption is that States are bound by customary international law because they have at least tacitly consented to it. Binding them to abide to customary practices despite their explicit rejection of these norms would violate their sovereign rights—though States are likely still bound in the case of peremptory, jus cogens norms which are thought to permit no State derogation, such as the international prohibition against genocide or slavery. See Colom v. Peru, 1950 I.C.J. 266 (Nov. 20); U.K. v. Norway, 1951 I.C.J. 116 (Dec.18).

Whitney, 124 U.S. at 194 (When…[a statute and treaty] relate to the same subject, the courts will always endeavor to construe them so as to give effect to both, if that can be done without violating the language of either; but, if the two are inconsistent, the one last in date will control the other: provided, always, the stipulation of the treaty on the subject is self-executing.").

Restatement, supra footnote 1, §102 (2) cmt. c. For a discussion of potential difficulties in relying U.N. General Assembly Resolutions as evidence of customary international law, see Oscar Schachter, International Law in Theory and Practice: General Course in Public International Law, 178 Rec. Des Cours 111-121 (1982-V).

See Sosa v. Alvarez-Machain, 542 U.S. 692, 738 (2004) (declining to apply protections espoused by the Universal Declaration of Human Rights because it "does not of its own force impose obligations as a matter of international law").

The Paquete Habana, 175 U.S. at 700. As a result, it is the opinion of some commentators that "no enactment of Congress may be challenged on the grounds that it violates customary international law." Wade Estey, The Five Bases of Extraterritorial Jurisdiction and the Failure of the Presumption Against Extraterritoriality, 21 Hastings Int'l. & Comp. L. Rev. 177, 180 (1997). See also Committee of U.S. Citizens Living in Nicaragua, 859 F.2d at 940.

Murray v. Schooner Charming Betsy, 6 U.S. (2 Cranch) 64, 118 (1804) (Marshall, J.) ("an act of Congress ought never to be construed to violate the law of nations if any other possible construction remains...."). But see Sampson v. Federal Republic of Germany, 250 F.3d 1145, 1151-54 (7^th Cir. 2001) (suggesting that given the "present uncertainty about the precise domestic role of customary international law," application of this canon of construction to resolve differences between ambiguous congressional statutes and customary international law should be used sparingly).

Restatement, supra footnote 1, §702, cmt. n.

Buell v. Mitchell, 274 F.3d 337 (6^th Cir. 2001), citing North Sea Continental Shelf (Federal Republic of Germany/Denmark; Federal Republic of Germany/The Netherlands) 1969 I.C.J. 51/52 (Feb. 20) & Restatement, supra footnote 1, §102 (2) cmt. k. & reporters' n. 6.

28 U.S.C. §1350.

For additional background on the ATS, see CRS Report RL32118, The Alien Tort Statute: Legislative History and Executive Branch Views, by [author name scrubbed], and CRS Report R42925, Kiobel v. Royal Dutch Petroleum Co.: Extraterritorial Jurisdiction Under the Alien Tort Statute, by [author name scrubbed].

630 F.2d 876 (2^nd Cir. 1980). The court based its conclusion that torture was prohibited under international law upon sources including, inter alia, U.N. resolutions, the U.N. Charter, and the Universal Declaration of Human Rights.

See, e.g., Flores v. Southern Peru Copper Corp., 343 F.3d 140 (2^nd Cir. 2003) (Peruvian plaintiffs brought personal injury claims under ATS against American mining company, alleging that pollution from mining company's Peruvian operations had caused severe lung disease); Abebe-Jira v. Negewo, 72 F.3d 844 (11^th Cir. 1996) (former prisoners in Ethiopia filed lawsuit under ATS against former Ethiopian official for torture); Kadic v. Karadzic, 70 F.3d 232 (2^nd Cir.1995) (Bosnian plaintiffs brought suit against the self-proclaimed leader of unrecognized Bosnian-Serbian entity under the ATS for war crimes).

542 U.S. 692 (2004).

Alvarez-Machain v. United States, 331 F.3d 604, 609 (9^th Cir. 2003) (en banc).

See United States v. Alvarez-Machain, 504 U.S. 655 (1992).

Sosa, 542 U.S. at 724.

Id. at 725.

Id. at 723. An Act To Declare the Treaties Heretofore Concluded with France, No Longer Obligatory on the United States, 1 Stat. 578 (1798).

Id. at 732.

Id. at 734-735.

Id. See also, e.g., Aldana v. Del Monte Fresh Produce, N.A., Inc., 416 F.3d 1242 (11^th Cir. 2005), cert. denied, 549 U.S. 1032 (2006) (while claim of torture was cognizable under ATS, claims of arbitrary detention and cruel, inhuman or degrading treatment were not); Taveras v. Taveraz, 477 F.3d 767 (6^th Cir. 2006) (cross-border child abduction by parent did not constitute violation of "law of nations" cognizable under ATS); Abdullahi v. Pfizer, Inc., 562 F.3d 163 (2^nd Cir. 2009) (jurisdiction existed under ATS for claim against private company that, with the aid of Nigerian government, allegedly violated customary international prohibition on non-consensual human medical experimentation), cert. denied, 130 S. Ct. 3541 (2010).

Kiobel v. Royal Dutch Petroleum Co., 133 S.Ct. 1659 (2013).

When the Supreme Court initially granted certiorari to consider the Kiobel case, it appeared that the central issue concerned whether corporations could be held liable under the ATS for violations of the laws of nations. After the first round of oral arguments, however, the Court directed the parties to file supplemental briefs on the question of the ATS's extraterritorial application and heard a second round of oral arguments on that issue. For further background, see CRS Legal Sidebar WSLG128, Supreme Court to Rehear Kiobel Case this Fall—Possible Repercussions for Human Rights Cases and Foreign Affairs, by [author name scrubbed].

Kiobel,133 S.Ct. at 1669. The majority opinion stated that "mere corporate presence" in the United States was not a sufficient nexus for ATS jurisdiction to attach over a multinational corporation's conduct outside the country. Id. Writing in concurrence, Justice Kennedy stated that the Court's opinion was "careful to leave open a number of significant questions regarding the reach and interpretation" of the ATS, including its extraterritorial "application to allegations of serious violations of international law principles protecting persons." Id. (Kennedy, J., concurring). Rejecting the presumption against extraterritoriality, Justice Breyer, also concurring and joined by three other members of the Court, would have held that ATS jurisdiction may attach when "(1) the alleged tort occurs on American soil, (2) the defendant is an American national, or (3) the defendant's conduct substantially and adversely affects an important American national interest, and that includes a distinct interest in preventing the United States from becoming a safe harbor (free of civil as well as criminal liability) for a torturer or other common enemy of mankind." Id. at 1671 (Breyer, J., concurring).

For discussion and analysis of the Kiobel case, see CRS Report R42925, Kiobel v. Royal Dutch Petroleum Co.: Extraterritorial Jurisdiction Under the Alien Tort Statute, by [author name scrubbed].

See, e.g. Curtis A. Bradley, Treaty Termination and Historical Gloss, 92 Tex. L. Rev. 773, 789 (2014); Fourth Restatement: Draft 2, supra note 28, § 113, reporters' n.2; Treaties and Other International Agreements, supra note 8, at 207.

See S. Rep. No. 34-97, at 5 (1856) (Senate Foreign Relations Committee describing the 1798 treaty abrogation statute as a "rightful exercise of the war power, without viewing it in any manner as a precedent establishing in Congress alone, and under any circumstances, the power to annul a treaty."). Cf. Bas v. Tingy, 4 U.S. (4 Dall.) 37, 40 (1800) (opinion of Washington, J.) (treating the 1798 statute as one in a bundle of congressional acts declaring a limited "public war" on the French Republic).

For analysis of 19th century understanding and practice related to treaty termination, see Bradley, supra note 203, at 788-801; Crandall, supra note 27, at 423-66.

See, e.g., Joint Resolution Concerning the Oregon Territory, 9 Stat. 109 (1846) (providing that the President "is hereby authorized, at his discretion, to give to the government of Great Britain the notice required by" a convention allowing for joint occupancy of parts of the Oregon Territory); Joint Resolution of June 17, 1874, 18 Stat. 287 (authorizing the President to give notice of termination of a Treaty of Commerce with Belgium).

See, e.g., Joint Resolution of Jan. 18, 1865, 13 Stat. 566 ("Resolved . . . That notice be given of the termination of the Reciprocity Treaty . . . and the President of the United States is hereby charged with the communication of such notice to the government of the United Kingdom . . . ."); Joint Resolution of Mar. 3, 1883, 22 Stat. 641 ("[T]he President . . . hereby is directed to give notice to the Government of Her Britannic Majesty that the provisions of each and every of the articles aforesaid will terminate . . . on the expiration of two years next after the time of giving such notice.").

See, e.g., Franklin Pierce, Third Annual Message (Dec. 31, 1855), in 7 A Compilation of the Messages and Papers of the Presidents 2860, 2867 (James D. Richardson ed., 1897) ("In pursuance of the authority conferred by a resolution of the Senate of the United States passed on the 3d of March last, notice was given to Denmark" that the United States would "terminate the [treaty] at the expiration of one year from the date of notice for that purpose.").

For example, after Congress enacted a joint resolution calling for the termination of the Oregon Territory Treaty, supra note 206, the Secretary of State informed the U.S. Ambassador to Great Britain that "Congress have spoken their will upon the subject, in their joint resolution; and to this it is his (the President's) and your duty to conform." S. Doc. 29-489, at 15 (1846). As required by the Joint Resolution of January 18, 1865, supra note 207, the Andrew Johnson Administration terminated an 1854 treaty with Great Britain concerning trade with Canada. Letter from William H. Seward, U.S. Sec'y of State, to Charles Francis Adams, Minister to the U.K. (Jan. 18, 1865), in Papers Relating to Foreign Affairs, pt. 1, at 93 (1866).

See, e.g., Joint Resolution to Terminate the Treaty of 1817 Regulating the Naval Force on the Lakes, 13 Stat. 568 (1865) ("[T]he notice given by the President of the United States to [the] government of Great Britain and Ireland to terminate the treaty . . . is hereby adopted and ratified as if the same had been authorized by Congress."); Joint Resolution of Dec. 21, 1911, 37 Stat. 627 (1911) (stating that President Taft's notice of termination of a treaty with Russia was "adopted and ratified").

See Bradley, supra note 203, at 807-09.

See, e.g., Comprehensive Anti-Apartheid Act of 1986, Pub. L. No. 99-440, § 313, 100 Stat. 1086, 1104 (mandating that "[t]he Secretary of State shall terminate immediately" a tax treaty and protocol with South Africa), repealed by South African Democratic Transition Support Act of 1993, Pub. L. No. 103-149, § 4, 107 Stat. 1503, 1505; Fishery Conservation and Management Act of 1976, Pub. L. No. 94-265, § 202(b), 90 Stat. 331, 340-41 (authorizing the Secretary of State to renegotiate certain fishing treaties and expressing the "sense of Congress that the United States shall withdraw from any such treaty, in accordance with its provisions, if such treaty is not so renegotiated within a reasonable period of time after such date of enactment").

See Bradley, supra note 203, at 807-15.

444 U.S. 996 (1979).

Mutual Defense Treaty Between the United States of America and the Republic of China, Dec. 2, 1954, 6 U.S.T. 433.

For background on Goldwater v. Carter, see Victoria Marie Kraft, The U.S. Constitution and Foreign Policy: Terminating the Taiwan Treaty 1-52 (1991).

See Goldwater, 444 U.S. at 996 (vacating with instructions to dismiss with no majority opinion).

See id. 1002-05 (Rehnquist, J., concurring) (joined by Justices Stewart and Stevens and Chief Justice Burger). Justice Powell also voted for dismissal, but did so based on the ground that the case was not ripe for judicial review until the Senate passed a resolution disapproving of the President's termination. See id. at 998 (Powell, J., concurring). Justice Brennan would have held that President Carter possessed the power to terminate the Mutual Defense Treaty with Taiwan, but his opinion centered on the President's power over recognition over foreign governments, and not because he believed the President possessed a general, constitutional power to terminate treaties. See id. at 1006-07 (Brennan, J., dissenting).

In 1986, a federal district court dismissed a group of private plaintiffs' suit seeking to prevent President Reagan from unilaterally terminating a Treaty of Friendship, Commerce, and Navigation with Nicaragua. See Beacon Products Corp. v. Reagan, 633 F. Supp. 1191, 1198-99 (D. Mass. 1986), aff'd on other grounds, 814 F.2d 1 (1st Cir. 1987).

In 2002, the United States District Court for the District of Columbia dismissed as nonjusticable a challenge brought by 32 Members of Congress to President George W. Bush's termination of the Anti-Ballistic Missile Treaty with Russia. See Kucinish v. Bush, 236 F. Supp. 2d 1, 14-17 (D.D.C. 2002).

Third Restatement, supra note 1, § 102(2).

Id. § 102 cmt. c.

Id.

Id. § 102, reporters' n. 2. The philosophy underlying the consistent objector exemption is that States are bound by customary international law because they have at least tacitly consented to it. Binding them to abide to customary practices despite their explicit rejection of these norms would violate their sovereign rights—though States are likely still bound in the case of peremptory, jus cogens norms which are thought to permit no State derogation, such as the international prohibition against genocide or slavery. See Colom v. Peru, 1950 I.C.J. 266 (Nov. 20); U.K. v. Norway, 1951 I.C.J. 116 (Dec.18).

See Whitney v. Robertson, 124 U.S. 190, 194 (1888) ("When . . . [a statute and treaty] relate to the same subject, the courts will always endeavor to construe them so as to give effect to both, if that can be done without violating the language of either; but, if the two are inconsistent, the one last in date will control the other: provided, always, the stipulation of the treaty on the subject is self-executing."). See also supra § Conflict with Existing Laws (discussing the "last-in-time rule").

Third Restatement, supra note 1, §102 (2) cmt. c. For a discussion of potential difficulties in relying U.N. General Assembly Resolutions as evidence of customary international law, see Oscar Schachter, International Law in Theory and Practice: General Course in Public International Law, 178 Rec. Des Cours 111-121 (1982-V).

See Sosa v. Alvarez-Machain, 542 U.S. 692, 738 (2004) (declining to apply protections espoused by the Universal Declaration of Human Rights because it "does not of its own force impose obligations as a matter of international law").

See, e.g., Sanchez-Llamas v. Oregon, 548 U.S. 331, 354 (2006) (while Optional Protocol of the Vienna Convention on Consular Relations, to which the United States was a party, gave the International Court of Justice jurisdiction to settle disputes between parties regarding the treaty's meaning, ruling by the international tribunal was not binding precedent on U.S. courts; if "treaties are to be given effect as federal law … determining their meaning as a matter of federal law is emphatically the province and duty of the judicial department, headed by the one [S]upreme Court established by the Constitution") (citations and quotations omitted).

Thirty Hogsheads of Sugar v. Boyle, 13 U.S. (9 Cranch) 191 (1815).

See, , e.g., Medellin, 552 U.S. at 507 (Court interpretation of international agreement may be aided by examining negotiating and drafting history and the post-ratification understanding of contracting parties); Zicherman v. Korean Air Lines Co., Ltd., 516 U.S. 217 (1996) (same); I.N.S. v. Cardoza-Fonseca, 480 U.S. 421, 439 n.22 (1987) (using U.N. interpretative materials to "provide significant guidance in construing" the 1967 United Nations Protocol Relating to the Status of Refugees); Air France v. Saks, 470 U.S. 392, 404 (1985) (finding that "the opinions of our sister signatories to be entitled to considerable weight" when interpreting agreement provisions); Sumitomo Shoji America, Inc. v. Avagliano, 457 U.S. 176, 184 n.10 (1981) (position of Japanese government entitled to great weight when interpreting provisions of U.S.-Japan treaty); Jordan v. Tashiro, 278 U.S. 123, 127 (1928) (finding that provisions of treaties "should be liberally construed so as to effect the apparent intention of the parties to secure equality and reciprocity between them").

Recent controversy has focused on citations to contemporary foreign law in U.S. courts' analyses of the meaning and scope of U.S. constitutional provisions. But citations to foreign law may also occur in other, sometimes less controversial, contexts. For example, a federal or U.S. state statute may recognize action taken by a foreign government as being relevant to the person's eligibility for a federal or state right or benefit (e.g., whether to recognize a marriage occurring in another country; or the implications that a foreign criminal conviction may have upon an non-citizen's ability under U.S. immigration laws to enter or remain in the United States). Litigation concerning these domestic statutes may occasionally compel U.S. courts to interpret and apply foreign law. Moreover, the law of a U.S. state may authorize the recognition of a foreign judgment or arbitration award. Further, a U.S. state's choice of law rules may require application of foreign law in certain civil disputes taking place between private parties (e.g., when a person brings suit against a person residing in the U.S. state on account of injurious activities that occurred overseas). In recent years, the possibility that U.S. state courts might apply religious law to settle family disputes, or might enforce an anti-defamation judgment of a foreign state which does not protect free speech to the same degree as the United States, has been the subject of legislative enactments at the state or federal level, and, in some instances, litigation. For discussion of these issues, see CRS Report R41824, Application of Religious Law in U.S. Courts: Selected Legal Issues, by [author name scrubbed], and CRS Report R41417, The SPEECH Act: The Federal Response to "Libel Tourism" (discussing the SPEECH Act, P.L. 111-223, which bars U.S. state and federal courts from recognizing or enforcing a foreign judgment for defamation unless certain requirements are satisfied, including consistency with the U.S. Constitution and Section 230 of the Communications Act of 1934, which accords legal protections to providers of interactive computer services which block or screen offensive material).

See generally Steven G. Calabresi and Stephanie Dotson Zimdahl, The Supreme Court And Foreign Sources Of Law: Two Hundred Years Of Practice And The Juvenile Death Penalty Decision, 47 Wm. & Mary L. Rev. 743 (2005) (discussing historical usage of foreign law by Supreme Court and controversy regarding usage in recent cases involving constitutional interpretation).

539 U.S. 558 (2003).

543 U.S. 551 (2005).

478 U.S. 186, 192 (1986).

Lawrence, 539 U.S. at 576-577. In dissent, Justice Scalia referred to the majority's discussion of foreign law as "meaningless ... [d]angerous dicta." Id. at 2495 (Scalia, J., dissenting).

Thompson v. Oklahoma, 487 U.S. 815 (1988).

Stanford v. Kentucky, 492 U.S. 361 (1989).

For further discussion, see CRS Report RS21969, Capital Punishment and Juveniles, by [author name scrubbed].

Id. at 578.

Ide.g., Andrew T. Guzman, Saving Customary International Law, 27 Mich. J. Int'l L. 115, 124-28 (2005) (discussing uncertainties associated with customary international law). See also Hamdan v. United States, 696 F.3d 1238, 1250 (D.C. Cir. 2012) (Kavanaugh, J.) ("It is often difficult to determine what constitutes customary international law, who defines customary international law, and how firmly established a norm has to be to qualify as a customary international law norm."), overruled on unrelated grounds by Al Bahlul v. United States, 767 F.3d 1 (D.C. Cir. 2014) (en banc).

Third Restatement, supra note 1, § 702, cmt. n.

Buell v. Mitchell, 274 F.3d 337 (6th Cir. 2001) (citing Comm. of U.S. Citizens Living in Nicaragua v. Reagan, 859 F.2d 929, 940 (D.C. Cir. 1988); Third Restatement, supra note 1, § 102 (2) cmt. k. & reporters' n. 6).

See The Nereide, 13 U.S. 388, 423, 3 L. Ed. 769 (1815) (Marshall, C.J.) ("[T]he Court is bound by the law of nations which is a part of the law of the land.); Respublica v. De Longchamps, 1 U.S. 111, 116 (Pa. O. & T. 1784) (describing a "crime in the indictment is an infraction of the law of Nations. This law, in its full extent, is part of the law of this State."). See also William Blackstone, Commentaries on the Laws of England 67 (1769) ("[T]he law of nations . . . is here adopted in its full extent by the common law, and is held to be a part of the law of the land.").

See, e.g., 1 Op. Atty Gen. 26, 27 (1792) ("The law of nations, although not specially adopted by the constitution or any municipal act, is essentially the law of the land."); 1 Op. Att'y Gen. 69, 69 (1797) ("[T]he common law has adopted the law of nations in its full extent, made it a part of the law of the land.); 5 Op. Att'y Gen. 691, 692 (1802) ("[T]he law of nations is considered as part of the municipal law of each State.").

175 U.S. 677, 700 (1900) ("International law is part of our law, and must be ascertained and administered by the courts of justice of appropriate jurisdiction as often as questions of right depending upon it are duly presented for their determination.").

Erie R.R. Co. v. Tompkins, 304 U.S. 64, 79 (1938) (describing the "assumption that there is a transcendental body of law outside of any particular State but obligatory within it unless and until changed by statute" as a fallacy) (internal quotations omitted).

Id.

See, e.g., Sosa v. Alvarez-Machain, 542 U.S. 692, 745-46 (2004) (Scalia, J., concurring) (arguing that customary international law would have been considered part of the "general common law" abolished by Erie); Curtis A. Bradley & Jack L. Goldsmith, Customary International Law As Federal Common Law: A Critique of the Modern Position, 110 Harv. L. Rev. 815, 852-55 (1997) (""After Erie . . . a federal court can no longer apply [customary international law] in the absence of some domestic authorization to do so, as it could under the regime of general common law.").

See, e.g., Third Restatement, supra note 1, § 111 reporters' n. 3 ("[T]he modern view is that customary international law in the United States is federal law . . . ."); Harold Hongju Koh, Is International Law Really State Law?, 111 Harv. L. Rev. 1824, 1835 (1998) ("[F]ederal courts retain legitimate authority to incorporate bona fide rules of customary international law into federal common law."); Beth Stephens, The Law of Our Land: Customary International Law As Federal Law After Erie, 66 Fordham L. Rev. 393, 397 (1997) ("[T]he suggestion that Erie tossed the law of nations out of federal court along with the general common law rests on several misconceptions.").

Banco Nacional de Cuba v. Sabbatino, 376 U.S. 398, 425 (1964) (discussing Philip C. Jessup, The Doctrine of Erie Railroad v. Tompkins Applied to International Law, 33 Am.J.Int'l L. 740 (1939)).

See Sosa, 542 U.S. at 730 ("We think it would be unreasonable to assume that the First Congress would have expected federal courts to lose all capacity to recognize enforceable international norms simply because the common law might lose some metaphysical cachet on the road to modern realism.").

For an overview of competing positions on the issue, see Bradley, supra note 35, at 140-58.

See, e.g., Guaylupo-Moya v. Gonzales, 423 F.3d 121, 136 (2d Cir. 2005) ("[C]lear congressional action trumps customary international law and previously enacted treaties.").

Accord Bradley, supra note 35, at 153.

The Paquete Habana, 175 U.S. 677, 700 (1900).

Murray v. Schooner Charming Betsy, 6 U.S. (2 Cranch) 64, 118 (1804) (Marshall, J.) ("[A]n act of Congress ought never to be construed to violate the law of nations if any other possible construction remains . . . ."). But see Sampson v. Fed. Republic of Germany, 250 F.3d 1145, 1151-54 (7th Cir. 2001) (suggesting that given the "present uncertainty about the precise domestic role of customary international law," application of this canon of construction to resolve differences between ambiguous congressional statutes and customary international law should be used sparingly); Al-Bihani v. Obama, 619 F.3d 1, 32–36, 42 (D.C. Cir. 2010) (Kavanaugh, J., concurring in denial of rehearing en banc) (arguing against the application of the Charming Betsy canon).

See infra notes 246-248.

16 U.S.C. § 1651 ("Whoever, on the high seas, commits the crime of piracy as defined by the law of nations, and is afterwards brought into or found in the United States, shall be imprisoned for life.");

28 U.S.C. § 1605(a)(3) (providing an exception to foreign sovereign immunity in any case "in which rights in property taken in violation of international law are in issue and that property or any property exchanged for such property is present in the United States in connection with a commercial activity carried on in the United States by the foreign state");

28 U.S.C. § 1350.

For more in-depth treatment of the ATS, see CRS Report R44947, The Alien Tort Statute (ATS): A Primer, by [author name scrubbed].

630 F.2d 876 (2nd Cir. 1980).

See Anthony D'Amato, Preface in The Alien Tort Claims Act: An Analytical Anthology vii (1999). See also Kiobel v. Royal Dutch Petroleum Co., 621 F.3d 111, 116 (2d Cir. 2010), aff'd on other grounds, 569 U.S. 108 (2013) ("Since [Filártiga], the ATS has given rise to an abundance of litigation in U.S. district courts."); Balintulo v. Daimler AG, 727 F.3d 174, 179 (2d Cir. 2013) (describing the ATS as "a statute, passed in 1789, that was rediscovered and revitalized by the courts in recent decades to permit aliens to sue for alleged serious violations of human rights 'occurring abroad."); Ingrid Wuerth, Kiobel v. Royal Dutch Petroleum Co.: The Supreme Court and the Alien Tort Statute, 107 Am. J. Int'l L. 601, 601 (2013) ("Since the 1980 court of appeals decision in Filártiga v. Peña-Irala permitting a wide of range human rights cases to go forward under the statute's auspices, the ATS has garnered worldwide attention and has become the main engine for transnational human rights litigation in the United States.").

542 U.S. 692 (2004).

Id. at 725.

Id. at 728.

Kiobel v. Royal Dutch Petroleum Co., 569 U.S. 108, 124 (2013).

See id.

Jesner v. Arab Bank, PLC, 138 S. Ct. 1386, 1407 (2018).

See, e.g., Chimène Keitner, ATS, RIP?, Lawfare (Apr. 25, 2018), https://lawfareblog.com/ats-rip.

See supra § Forms of International Agreements.

See § Self-Executing vs. Non-Self-Executing Agreements.