On June 17, 2021, the U.S. Supreme Court delivered its opinion in Nestlé USA, Inc. v. Doe, a human rights case brought under the Alien Tort Statute (ATS), alleging that U.S. companies aided and abetted child slavery in Ivory Coast. By a vote of 8 to 1, the Court held that the claims were impermissibly extraterritorial because nearly all the conduct occurred abroad. The Court left open the possibility that the implied cause of action under the ATS applies to U.S. corporations.

The significance of Department of Defense (DOD) Directive 2311.01E, The Law of War Program (DODD 2311.01E), last updated in 2020, is not simply rhetorical. Born in 1974 in immediate reaction to the well-publicized atrocities committed by U.S. service members in Vietnam (such as at My Lai and Song Thang), the original directive represented the most tangible and highest-level expression of the U.S. executive branch's desire that its members comply with the laws and customs of war. Beyond important symbolism, the original regulation created a true law of war program in more than name only by establishing an interrelated set of measures focused on training, reporting, and investigating with designated offices and positions of responsibility—measures expressly crafted to ensure law of war adherence. DODD 2311.01E maintains and improves the original 1974 program's compliance architecture, and in doing so operationalizes, more than any other DOD or military initiative, the U.S. national commitment that its military should live by the law of war's precepts.

On June 8, 2021, the UN International Residual Mechanism for Criminal Tribunals (Mechanism) Appeals Chamber delivered its appeals judgment in Prosecutor v. Ratko Mladić. The judgment affirmed the 2017 trial judgment of Trial Chamber I of the UN International Criminal Tribunal for the former Yugoslavia (ICTY), which convicted Mladić, the Bosnian Serb commander, of genocide, crimes against humanity, and war crimes during the war in Bosnia between 1992 and 1995, as well as affirming his sentence of life imprisonment. This constituted Mladić's final appeal, opening the door for his assignment to a prison somewhere in Europe.

On October 26, 2021, the Court of Justice of the European Union (CJEU) issued its judgment in Case C-109/20 Poland v. PL Holdings. The case concerned an arbitral award issued in favor of PL Holdings against Poland. The arbitration clause which served as the basis for resolving the parties’ dispute is contained in a 2017 bilateral investment treaty between Poland and the Belgium-Luxembourg Economic Union (BLEU BIT). One year after the award was made, the CJEU ruled in Achmea that intra-EU investor-state arbitration clauses in treaties between EU member states are incompatible with EU law. The Court conversely held that commercial arbitration was compatible with EU law because it is an expression of the will of the parties, rather than a consequence of a treaty between states. Poland used Achmea to argue against the arbitral tribunal's jurisdiction, but the objection was considered by the Arbitration Institute of the Stockholm Chamber of Commerce to have been registered too late and Poland was ordered to pay damages to PL Holdings. Poland then brought an action before the Svea Court of Appeal (Svea hovrätt) to set aside the award, based on the invalidity under EU law of the arbitration clause in the BLEU BIT. Though the Swedish court accepted that, based on Achmea, the clause was invalid, it held that Poland's late objection to the jurisdiction of the tribunal and subsequent arbitration with PL Holdings meant that an ad hoc arbitration agreement had been established between the parties that was not precluded by Achmea and thus, the Court denied Poland's request to set aside the award. Poland appealed to the Supreme Court of Sweden (Högsta domstolen), which requested a preliminary ruling from the CJEU as to whether “Articles 267 and 344 TFEU precluded the conclusion of an ad hoc arbitration agreement between the parties to the dispute where the content of that agreement is identical to an arbitration clause that is set out in the BIT and is contrary to EU law.” The CJEU answered this question in the affirmative.