On January 28, 2021, a Special Chamber of the International Tribunal for the Law of the Sea (ITLOS) dismissed all of the respondent's preliminary objections in Dispute Concerning Delimitation of the Maritime Boundary Between Mauritius and Maldives in the Indian Ocean (Mauritius/Maldives). The proceeding arose out of Mauritius's long-running effort to regain sovereignty over the Chagos Archipelago, which was originally “detached” from Mauritius in 1965 by the United Kingdom (UK). Although the Judgment will allow the case to proceed to the merits, it is significant in its own right for its engagement with several earlier legal decisions, including the arbitral award in Chagos Marine Protected Area Arbitration and the International Court of Justice's (ICJ) Advisory Opinion on the Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, as well as UN General Assembly Resolution 73/295 affirming the Advisory Opinion. The Special Chamber stitched together a series of legal documents that, considered individually, were either non-binding or limited in scope to achieve a determination greater than the sum of its parts—one that effectively resolved the disputed sovereignty over the Chagos Archipelago.

On October 6, 2020, the Court of Justice of the European Union (CJEU) handed down its judgment in Commission v. Hungary. It found that Hungary had violated the General Agreement on Trade in Services (GATS), as well as internal European Union law—specifically the EU Charter of Fundamental Rights (EU Charter). The case arose out of Hungary's 2017 amendment to its higher education law. The amendment imposed two novel requirements on foreign universities operating in Hungary. It barred any non-EU university from operating unless its country of origin concluded a specific enabling treaty with Hungary. Moreover, it required that the foreign university actually provide educational services in its country of origin. While framed in general terms, it is hard to avoid the conclusion that the 2017 amendment was aimed at ending the operations of the Central European University (CEU) in Hungary.

The Judgment of the Court of Justice of the European Union (CJEU) in Slovenia v. Croatia marks the anticlimax of a long-running territorial dispute. It is also only the sixth time the CJEU has issued a judgment in a case instituted by one European Union member against another. Among these cases, it is the first to consider an arbitral award in a dispute between members, the first to consider a boundary dispute between members, and the first to be dismissed for lack of jurisdiction. The Court found that it cannot rule on alleged infringements of European Union law when these arise from the breach of a treaty falling outside of the Union's subject-matter competence. Most directly, the Judgment may pose significant consequences for European Union internal affairs in the near term, such as Croatia's ambitions to join the Schengen Area and the Eurozone. More broadly, several of the Court's findings will be relevant beyond the European legal order, particular those concerning the meaning and effect of “ancillary” legal questions, and the bilateral or multilateral character of a dispute involving admission to an international organization.

In two nearly identical judgments dated July 14, 2020, the International Court of Justice (ICJ or Court) reviewed a decision taken by the Council of the International Civil Aviation Organization (ICAO) in a dispute about aviation restrictions imposed on Qatar by Bahrain, Egypt, Saudi Arabia, and the United Arab Emirates (UAE). These cases represent the second time that the Court has heard an appeal concerning a decision of the ICAO Council, a treaty body which has executive, administrative, and dispute settlement functions. As in 1972, when the Court heard an appeal brought by India against Pakistan, the Court's 2020 judgments concern a Council decision on preliminary objections to jurisdiction and admissibility. These judgments not only reinforce the ICJ's findings in its 1972 judgment, which raised similar procedural issues, but they also highlight the scope and the limits of the Court's rare appellate function.

In Nevsun Resources Ltd. v. Araya, the Supreme Court of Canada declined to dismiss a series of customary international law claims brought by Eritrean refugees against a Canadian mining corporation for grave human rights abuses committed in Eritrea. In doing so, the Supreme Court opened the possibility of a novel front for transnational human rights litigation: common law tort claims based on customary international law. Under the doctrine of adoption, customary international law is directly incorporated into the Canadian common law. However, Canadian courts have not yet upheld a private right of action for violations of customary international law. Writing for a divided court (5–4), Justice Abella allowed the plaintiffs’ claims to proceed, finding that it is not “plain and obvious” that the plaintiffs’ customary international law claims are bound to fail under either Canada's burgeoning “transnational” or “foreign relations” law, or international law itself. In reaching this conclusion, she offered a unique and overdue reflection on the role of national courts in identifying, adopting, and developing custom. A larger majority of the court (7–2) also rejected outright the application of the act of state doctrine in Canada, tracking several common law systems in limiting the doctrine in favor of human rights litigants.

On February 6, 2020, the Inter-American Court of Human Rights (Court) declared in Lhaka Honhat Association v. Argentina that Argentina violated Indigenous groups’ rights to communal property, a healthy environment, cultural identity, food, and water. For the first time in a contentious case, the Court analyzed these rights autonomously based on Article 26 of the American Convention on Human Rights (ACHR) and ordered specific restitution measures, including actions to provide access to adequate food and water, and the recovery of forest resources and Indigenous culture. The decision marks a significant milestone for protecting Indigenous peoples’ rights and expanding the autonomous rights to a healthy environment, water, and food, which are now directly justiciable under the Inter-American human rights system.

After Russia targeted the 2016 presidential election, U.S. government authorities repeatedly warned about the prospects of foreign interference in and influence on the 2020 election. Throughout the fall of 2020, government officials and private companies took a number of actions to address threats to the election, including issuing public warnings, imposing sanctions, and taking down foreign government-linked accounts. In a declassified report released in March 2021, the intelligence community concluded that although Russia and Iran carried out influence operations to affect the election, there are “no indications that any foreign actor attempted to alter any technical aspect of the voting process in the 2020 US elections, including voter registration, casting ballots, vote tabulation, or reporting results.” In December 2020, however, U.S. cybersecurity firm FireEye disclosed that it suffered a breach by a nation-state sponsored actor, and numerous U.S. government agencies soon revealed that they too had been breached in intrusions widely attributed to Russia.

In late 2016, officials at U.S. and Canadian diplomatic posts in Havana, Cuba, began reporting a cluster of symptoms, including nausea, severe headaches, and dizziness, that came to be known as “Havana Syndrome.” The illnesses prompted the departure of U.S. personnel from Havana in 2017, and subsequent cases have been reported among personnel assigned to the U.S. consulate in Guangzhou, China and elsewhere. In recent months, three reports related to the illnesses and the government's response have become public. A Center for Disease Control (CDC) report examined medical records and produced a case definition. A National Academies for Sciences, Engineering, and Medicine (NASEM) standing committee considered possible causes, including “directed, pulsed radio frequency (RF) energy, . . . chemical exposures, infectious diseases and psychological issues,” and concluded that the symptoms were consistent with RF effects. Additionally, a recently declassified Accountability Review Board (ARB) report criticized the Trump administration's response to the illnesses in Havana. Amid reports of increasing cases, including some occurring in the United States, the Biden administration is attempting to determine the cause of the illness and has committed to support affected personnel.

The Biden administration's foreign policy emphasizes repairing U.S. alliances and returning the United States to a “position of trusted leadership” to counter increasing challenges from Russia and especially China. The U.S. Interim National Security Strategic Guidance (INSSG), released in March 2021, notes that the United States must “contend with the reality that the distribution of power across the world is changing.” It highlights that China, which has “rapidly become more assertive,” is the only country “potentially capable of combining its economic, diplomatic, military, and technological power to mount a sustained challenge to a stable and open international system,” while “Russia remains determined to enhance its global influence and play a disruptive role on the world stage.” To reaffirm established international norms, the Biden administration has acted both unilaterally and in coordination with long-standing allies to impose sanctions in response to human rights abuses, malicious cyber activity, and election influence. The administration has also taken steps to cement alliances in the Indo-Pacific and with the West.

On December 10, 2020, President Donald J. Trump reversed decades of U.S. policy by announcing that the United States would recognize Moroccan sovereignty over Western Sahara as part of a deal in which Morocco would normalize relations with Israel. Despite a 1991 UN truce and continued calls by the UN Security Council for Morocco and the Polisario Front to reach a mutually agreeable solution, neither side has relinquished its claim of sovereignty over Western Sahara. Trump's announcement ended nearly thirty years of U.S. support for UN-led negotiations and places the United States at odds with the majority of the international community, which swiftly criticized the U.S. action as a violation of the right to self-determination.

In July, the United States, the North Atlantic Treaty Organization (NATO), the European Union (EU), and other allies attributed a variety of malicious cyber activities, including the Microsoft Exchange hack, to China. This joint attribution builds on commitments made in June summits with NATO, the G7, the EU, and the United Kingdom, and is consistent with the Biden administration's multilateral approach to confronting cybersecurity threats and China more generally. Still, critics question whether the administration's efforts will succeed in altering the behavior of states that pose cybersecurity threats to the United States.

In September and October 2020, Kosovo, Serbia, the United Arab Emirates (UAE), Bahrain, and Sudan normalized relations with Israel in a flurry of agreements brokered by the United States. President Donald Trump suggested that, in addition to being valuable on their own terms, the agreements were part of a broader diplomatic effort to pressure the Palestinians into negotiating a peace deal with Israel. In December, the White House announced normalization of relations between Israel and Morocco in apparent exchange for U.S. recognition of Moroccan sovereignty over the disputed territory of Western Sahara.

On May 23, 2021, Belarusian authorities forced a Ryanair flight from Athens, Greece to Vilnius, Lithuania to land in Minsk in response to a false bomb threat and then arrested Roman Protasevich, an exiled journalist onboard the flight. The United States joined much of the international community in condemning the flight's diversion and imposing additional sanctions on Belarusian President Alexander Lukashenko's regime, adding to those levied throughout the last year due to Lukashenko's repression of opposition figures and others who have protested the results of the August 2020 Belarusian election.

The newly inaugurated administration of President Joseph R. Biden, Jr. took immediate steps to reengage with a variety of international institutions and agreements from which the Trump administration had withdrawn. On January 20, 2021, the administration deposited with the United Nations a new instrument of acceptance of the Paris Agreement on climate change, and it halted U.S. withdrawal from the World Health Organization (WHO). On January 21, the United States announced that it would participate in the COVID-19 Vaccines Global Access (COVAX) Facility, an international vaccine distribution scheme. The Biden administration also announced that it would reengage with and seek election to the UN Human Rights Council, and it quickly reached agreement with Russia for a five-year extension of the New Strategic Arms Reduction Treaty (New START), the last remaining arms control agreement between the two countries. These early moves are consistent with the foreign policy strategy President Biden previewed during the campaign when he promised to “renew American leadership” and “[e]levate [d]iplomacy.” In his first speech on foreign policy as president, delivered at the U.S. State Department on February 4, Biden asserted that “America is back” and that “[d]iplomacy is back at the center of our foreign policy.” To implement these objectives, Biden has appointed a slate of experienced foreign affairs officials, many of whom worked in the Obama administration.

On September 15, 2020, a World Trade Organization (WTO) panel ruled that certain tariffs the United States imposed on Chinese products violated Articles I (most-favored-nation) and II (tariff bindings) of the General Agreement on Tariffs and Trade (GATT). The panel rejected the U.S. attempt to invoke a “public morals” defense pursuant to GATT Article XX, holding that although countries receive substantial deference in defining “public morals,” the United States failed to prove that the tariffs were necessary to achieve its stated public morals objective.

The Biden administration has undertaken to reset U.S. relations with Saudi Arabia, making early moves to break with the Trump administration's policy toward the country on several key fronts. White House officials have shifted the locus of diplomatic contact between the two countries from Saudi Crown Prince Mohammed bin Salman, who enjoyed a close relationship with the Trump administration, to his father, King Salman. U.S. officials publicly released an intelligence report accusing Prince Mohammed of ordering the 2018 killing of Saudi dissident and Washington Post columnist Jamal Khashoggi and levied travel sanctions against seventy-six Saudi nationals in the crown prince's orbit. President Biden has also taken steps to end U.S. support for the Saudi-led coalition fighting in Yemen's civil war, revoking the terrorist designation assigned to the Houthi rebels in the final days of the Trump administration and initiating a review of U.S. arms sales.

In Federal Republic of Germany v. Philipp, the U.S. Supreme Court unanimously held that a country's taking of property from its own nationals does not fall within the Foreign Sovereign Immunities Act (FSIA) exception for “rights in property taken in violation of international law.” The case involved a claim that Nazi officials coerced a consortium of three art firms owned by Jewish residents of Germany to sell a collection of “medieval relics and devotional objects known as the Welfenschatz” to Prussia for “approximately one-third of their value.” The plaintiffs—descendants of the members of the consortium—argued that the coerced sale constituted genocide, thus bringing their claim within the FSIA exception. The Supreme Court disagreed, holding that “the expropriation exception is best read as referencing the international law of expropriation rather than of human rights” and that international law does not bar a state's taking of the property of its own nationals. The Court declined to reach Germany's alternative argument that international comity required dismissal of the case, and it vacated and remanded a companion case, Republic of Hungary v. Simon, that also posed the comity question.

In the final months of his administration, President Donald Trump issued a variety of pardons and commutations, including a number related to foreign relations. His decision to issue full pardons to four former Blackwater contractors, who were convicted of killing Iraqi civilians in the 2007 Nisour Square incident, drew particular condemnation and continued a pattern of clemency grants related to war crimes committed abroad. Trump also granted clemency to his former national security advisor, Michael Flynn, and other associates who were convicted as a result of Special Counsel Robert S. Mueller III's investigation into Russian interference in the 2016 presidential election. Additionally, Trump pardoned the Israeli handler of Jonathan Pollard, a convicted U.S. spy.

On April 1, 2021, the Biden administration issued an executive order reversing the Trump administration's sanctions on International Criminal Court (ICC) personnel. The administration rescinded the sanctions placed upon the ICC prosecutor, Fatou Bensouda, and the head of the Office of the Prosecutor's Jurisdiction, Complementarity, and Cooperation Division, Phakiso Mochochoko, and removed the officials from the Treasury Department's Office of Foreign Assets Control List of Specially Designated Nationals and Blocked Persons. The ICC, European Union (EU), and human rights groups welcomed the reversal.

The Trump administration is engaged in an ongoing legal battle against the makers of two Chinese smartphone applications, TikTok and WeChat, over their data-collection and content moderation practices. The administration has used both the International Emergency Economic Powers Act (IEEPA) and the Committee on Foreign Investment in the United States (CFIUS) in an attempt to force the companies to cease U.S. operations and, in TikTok's case, to change ownership. The administration's actions have spurred multiple legal challenges, several of which are ongoing, and for now, both TikTok and WeChat remain in operation in the United States.