The CJEU held that the United Kingdom of Great Britain and Northern Ireland (UK) is allowed to unilaterally revoke the notification of its intention to withdraw from the European Union (EU) as long as the revocation is submitted in writing to the European Council before the UK's withdrawal takes effect, and as long as the revocation is “unequivocal and unconditional, that is to say that the purpose of that revocation is to confirm the EU membership of the member state concerned under terms that are unchanged as regards its status as a member state, and that revocation brings the withdrawal procedure to an end” (para. 74).

In Yesh Din v. Chief of General Staff, IDF, the Israeli Supreme Court (Court) unanimously dismissed two petitions by six human rights NGOs who challenged the rules of engagement (RoE) governing Israel Defense Forces (IDF) activities in clashes near the fence separating the Gaza Strip and Israel between March and May 2018. The decision discusses several controversial international law issues relating to the use of force in response to cross-border mass demonstrations. In addition, it provides a closer look at the application of international law by a domestic court that is conscious of a potential International Criminal Court (ICC) investigation.

In Georgia v. Russia (I) (Just Satisfaction), the Grand Chamber of the European Court of Human Rights (ECtHR or Court) ordered the Russian Federation to pay Georgia EUR 10 million as reparation for Russia's “coordinated policy of arresting, detaining and expelling Georgian nationals” in the autumn of 2006 (paras. 51, 80). In so doing, the Court reaffirmed its position from Cyprus v. Turkey (IV) (Just Satisfaction) that financial compensation for non-pecuniary damage can be awarded in interstate cases. Although Georgia v. Russia (I) (Just Satisfaction) marks the development of a new line of ECtHR jurisprudence, it is unlikely that the decision will effectively prevent further mass violations of the European Convention on Human Rights (ECHR or Convention) by the states parties or offer fair compensation to the victims of such violations.

The Colombian Constitutional Court (Court) ordered the Colombian government to seek the restitution of a set of 122 golden objects of the Quimbaya people in a judgment issued on October 19, 2017 (Judgment). The Judgment addressed significant issues of international law relating to unilateral acts, treaty interpretation, cultural property (particularly that of indigenous peoples), and the settlement of disputes involving claims for restitution of cultural property through diplomacy and mediation.

In Jam v. International Finance Corp., the U.S. Supreme Court held that the International Organizations Immunities Act of 1945 (IOIA) affords international organizations (IOs) the same immunity from suit in U.S. courts that foreign governments currently enjoy under the Foreign Sovereign Immunities Act of 1976 (FSIA), which codifies the restrictive theory of foreign sovereign immunity. The International Finance Corporation (IFC) had argued that the IOIA, which grants international organizations the “‘same immunity’ from suit … ‘as is enjoyed by foreign governments’” (p. 15), should be understood to provide international organizations with absolute immunity, which it argued foreign governments enjoyed prior to the United States’ explicit adoption of the restrictive theory in 1952. Under the restrictive theory, a foreign state is immune from suit for its sovereign acts (acta jure imperii), but not for its commercial acts (acta jure gestionis). By interpreting language in the IOIA as granting the “same immunity” to international organizations as foreign governments enjoy at the time the suit is filed, the Supreme Court aligned the regime for IO immunity with that of foreign state immunity, except in cases where the IO's founding charter provides a different rule or where the executive branch has explicitly limited immunity. It remains to be seen what IO activities are deemed “commercial” under this regime and what types of transactions are found to have a sufficient nexus to the United States to fall within the FSIA's commercial-activity exception.

In October of 2018, the Trump administration announced that the United States would withdraw from four international agreements. On October 3, 2018, Secretary of State Mike Pompeo announced that the United States would withdraw from the Treaty of Amity, Economic Relations, and Consular Rights with Iran. Later that day, National Security Advisor John Bolton announced that the United States was also withdrawing from the Optional Protocol to the 1961 Vienna Convention on Diplomatic Relations (VCDR). Both withdrawals were triggered by pending International Court of Justice (ICJ) cases grounded in these treaties that were recently brought against the United States. Two weeks later, in an escalation of the ongoing trade dispute with China, the United States gave notice of withdrawal from the Universal Postal Union (UPU), the international body charged with overseeing the international mailing system. Finally, on October 22, 2018, President Trump announced that the United States would be terminating the Intermediate-Range Nuclear Forces (INF) Treaty with Russia. Unlike other withdrawals undertaken by the Trump administration, this latest round involved three Article II treaties to which the Senate had provided its advice and consent. In addition, the international commitments withdrawn from in this round were long-standing ones, with U.S. participation in the UPU going back as far as 1875.

The ruling of the Spanish Supreme Court in Judgment No. 1263/2018, recognizing, for the first time, the binding character of the Views of the Committee on the Elimination of Discrimination against Women (CEDAW Committee), augmented the normative authority of the Views of the human rights treaty monitoring body, not only at the domestic level, but also within the international legal sphere. In the Judgment, the Spanish highest court held that the government must comply with the Views of the CEDAW Committee as a matter of the state's constitutional mandate as well as its international obligations. The Court's interpretation in this case meets the expectation of human rights treaty monitoring bodies that states are obligated to respond to their Views concerning individual communications, despite some states parties’ claims to the contrary.

On September 6, 2018, Pre-Trial Chamber I of the International Criminal Court (ICC or Court) ruled by a majority—Judge Perrin de Brichambaut dissenting—that it has jurisdiction to hear cases concerning crimes that occurred only in part within the territory of a state party to the Rome Statute. In so ruling, the Court granted the ICC prosecutor's request to rule on jurisdiction and confirmed its territorial jurisdiction over the alleged deportation of Rohingya people from the territory of Myanmar (a state not party to the Rome Statute) to Bangladesh (a state party). The Court also affirmed unequivocally its objective international legal personality vis-à-vis non-party states and hinted strongly that the prosecutor should consider the possible prosecution of at least two additional crimes in connection with this situation.

The Trump administration undertook a variety of actions related to the southern U.S. border in late 2018 and early 2019. Pointing to the progress of thousands of migrants traveling together from Central America to the U.S. border, President Trump deployed troops to the border and issued a proclamation providing that access to asylum would only be available at the southern border to those who entered through an authorized port of entry. Legal challenges to this proclamation and its implementation by the Department of Homeland Security (DHS) immediately followed, and a federal district court issued a temporary restraining order on November 19 and a preliminary injunction on December 19 against its enforcement. In addition, after ongoing negotiations with Mexico, the Trump administration announced that it would implement an arrangement under which asylum seekers would await their court date in Mexico rather than the United States. These ongoing developments are part of broader attempts by the Trump administration to erect barriers to migration across the southern border.

On October 30, 2018, the South Korean Supreme Court, in an 11–2 decision, upheld the judgment of the lower court, which ordered New Nippon Steel Corporation, a Japanese company, to provide KRW 100 million (approximately USD 84,000) in compensation to each of the four plaintiffs, who were forced to work at Japanese steel mills during World War II. In an earlier 2012 decision, the Supreme Court remanded the case after holding that the claims were not precluded by the Agreement on the Settlement of Problems Concerning Property and Claims and the Economic Cooperation Between the Republic of Korea and Japan (Claims Agreement). The Supreme Court held that the Claims Agreement was not a result of negotiation about compensation for Japanese colonization, but rather was a political agreement the purpose of which was to resolve the financial and civil debt/credit relationship between Korea and Japan. On the final appeal, the Supreme Court concluded that plaintiffs’ claims were directly related to the illegality of Japan's colonial rule over the Korean Peninsula and that the rights of the victims of forced labor to make a compensation claim did not fall within the scope of the Claims Agreement.

On October 9, 2018, President Trump signed into law a statute that implements the Marrakesh Treaty to Facilitate Access to Published Works for Persons Who Are Blind, Visually Impaired or Otherwise Print Disabled (Marrakesh Treaty). The implementing legislation broadens access to published works for persons with visual disabilities and paves the way for the United States to ratify the Marrakesh Treaty.

In a speech before the National Rifle Association (NRA) on April 26, 2019, President Trump announced that he was requesting the return of the Arms Trade Treaty (ATT) from the Senate and that the United States would unsign this treaty. Shortly thereafter, Trump issued a formal letter to the Senate requesting the ATT's return. As of late September, the Senate had not formally approved Trump's request. Nonetheless, on July 18, 2019, the Trump administration communicated to the secretary-general of the United Nations that the United States does not intend to become a party to the ATT and thus has no future legal obligations stemming from signature.

In late 2018, the American Law Institute released a volume of the Restatement Fourth of the Foreign Relations Law of the United States. Initiated in October 2012 under the direction of Coordinating Reporters Sarah Cleveland and Paul Stephan, this volume covers three areas of U.S. foreign relations law: treaties, jurisdiction, and sovereign immunity. It remains to be seen whether the American Law Institute will revisit other portions of the Restatement Third, which was published in 1987. “[I]n the meantime, the provisions of the Third Restatement remain the position of The American Law Institute except where superseded by provisions in this Fourth Restatement.”

The Trump administration formally recognized Juan Guaidó as the interim president of Venezuela on January 23, 2019, making the United States the first nation to officially accept the legitimacy of Guaidó’s government and reject incumbent President Nicolás Maduro's claim to the presidency. In a campaign designed to oust Maduro from power, the United States has encouraged foreign governments and intergovernmental organizations to recognize Guaidó and has imposed a series of targeted economic sanctions to weaken Maduro's regime. As of June 2019, however, Maduro remained in power within Venezuela.

While Palestine considers itself a state, the United States does not currently recognize it as such. The relationship between the two has continued to deteriorate following the December 2017 announcement that the United States would recognize Jerusalem as Israel's capital and move its embassy there. Alleging that the embassy relocation violates international law, Palestine brought a case against the United States in the International Court of Justice (ICJ) in September of 2018. The United States reacted by announcing its withdrawal from the Optional Protocol to the Vienna Convention on Diplomatic Relations Concerning the Compulsory Settlement of Disputes (Optional Protocol). Also in the fall of 2018, the Trump administration closed the Palestine Liberation Organization (PLO) office in Washington, curtailed its own Palestinian-focused mission in Jerusalem, and sharply cut U.S. funding focused on Palestinian interests.

In July of 2019, the U.S. Senate gave advice and consent to protocols updating tax treaties with Spain, Switzerland, Japan, and Luxembourg, after a nearly decade-long period during which no tax treaties were approved by the Senate. This drought was primarily due to the privacy concerns of a single senator, Rand Paul of Kentucky, who deployed the Senate's procedural rules to increase the difficulty of the advice and consent process. Tax treaties with Hungary, Chile, and Poland, as well as a protocol to a multilateral tax convention, remained pending in the Senate Foreign Relations Committee as of mid-August of 2019.

A twenty-four-year-old agreement was reborn on October 1, 2018, when President Trump announced that the North American Free Trade Agreement (NAFTA) had been successfully renegotiated. The deal came after an arduous, year-long negotiation process that almost left Canada behind. As one indicator of its contentiousness, the deal lacks an agreed-upon name, but the United States is referring to it as the United States-Mexico-Canada Agreement (USMCA). It keeps some key NAFTA provisions mostly the same, including with respect to state-to-state dispute resolution, but eliminates, modifies, and adds other provisions. Among the changes: investor-state dispute settlement has been eliminated as between the United States and Canada; rules of origin for automobiles and rules for U.S. dairy products have been modified; and new provisions address labor protections, intellectual property rights, rights for indigenous persons, rules for trade negotiations with non-market countries, and the agreement's termination. The agreement was formally signed by the leaders of all three countries on November 30, 3018. It must be approved through the domestic ratification procedures of the three countries before it enters into force.

On April 8, 2019, President Trump announced that his administration would designate Iran's Islamic Revolutionary Guards Corps (IRGC) as a foreign terrorist organization (FTO) under Section 219 of the Immigration and Nationality Act (INA). This is the first time the United States has designated an arm of another government, rather than a non-state actor, as an FTO. In his announcement, Trump asserted that the Iranian government has used the IRGC to engage in a campaign of global terrorism. The measure, which officially took effect on April 15, expands on previous terrorism-related sanctions imposed on the IRGC and Iran.

On December 1, 2018, Canadian authorities arrested Meng Wanzhou, the chief financial officer of Chinese telecom manufacturer Huawei, in Vancouver as she was going from Hong Kong to Mexico. Meng, who has been charged by the U.S. Department of Justice with crimes relating to violations of U.S. sanctions on Iran, is currently awaiting an extradition hearing in Canada. Her arrest has complicated efforts to reach a resolution to the ongoing U.S-China trade dispute while straining relations between China and Canada, which is seeking the release of several Canadians detained by China in apparent retaliation for Meng's arrest.

With only three remaining members of what is supposed to be a seven-member body, the World Trade Organization's (WTO) Appellate Body may soon cease to function. Since 2016, the United States has blocked the reappointment of Appellate Body members and rejected over a dozen proposals to launch selection processes that could fill the remaining vacancies. As a lead reason for these blocks, the United States has cited concerns about the practice whereby members whose terms have expired continue to serve on appeals to which they were previously appointed. On December 10, 2019, the terms of two Appellate Body members will expire, leaving only one member remaining. Because the WTO's dispute settlement process requires three Appellate Body members for each appeal, WTO members will be unable to make any new appeals by this year's end unless a solution emerges to the current impasse.