Domestic courts frequently apply foreign law. For example, the forum's choice-of-law rules may require a court to apply foreign law, or a party may expressly base a claim or defense on foreign law. Private international law (or “conflict of laws”) provides principles governing many aspects of the way courts should identify and interpret foreign law.

On June 11, 2019, the United Nations (UN) Security Council unanimously adopted Resolution 2474 on missing persons in armed conflict. The resolution marks the first time the Security Council has agreed on a thematic text dedicated to this issue, lending its collective voice to call for more effective implementation of existing obligations towards missing persons—both civilian and military—and their families under international law.

On June 11, 2018, the State of Qatar (Qatar) instituted legal proceedings against the United Arab Emirates (UAE) before the International Court of Justice (ICJ), alleging violations of the International Convention on the Elimination of All Forms of Racial Discrimination (CERD Convention). On the same day, Qatar also applied for provisional measures of protection.

The judgment of the European Court of Human Rights (ECtHR, or the Court) in Mammadov v. Azerbaijan was the first “infringement procedure” judgment pursuant to Article 46(4) of the European Convention on Human Rights (ECHR, or the Convention). This procedure was introduced to the Convention by Protocol 14, which entered into force in 2010. The idea behind it was that the Committee of Ministers—the body of the Council of Europe that supervises the execution of judgments of the ECtHR—could return the case to the Court to confirm that the responded state had failed to enforce it. Although there are quite a few instances of non-execution, this procedure has not been in use because it is difficult to initiate and its results are uncertain. The Mammadov judgment was a test of the effectiveness of infringement procedures, but it failed to provide a definitive answer as to whether such procedures were effective in terms of state implementation of ECtHR judgments. The applicant in this case was a political prisoner and the Committee of Ministers fruitlessly tried for a number of years to force Azerbaijan to release him. Soon after the Article 46(4) request reached the Court, the Azerbaijani authorities conditionally released the applicant. That said, all other negative consequences of his criminal conviction, such as an inability to run for election, have yet to be removed, so the judgment has not been implemented in full.

On April 30, 2019, the Court of Justice of the European Union (CJEU) rendered Opinion 1/17 on the compatibility with European Union (EU) law of the Investment Court System (ICS) under the Comprehensive Economic and Trade Agreement between Canada and the European Union and its member states (CETA). In a momentous decision that is likely to have consequences beyond the CETA, a full court of the CJEU held that the ICS provisions were compatible with EU law.

On July 25, 2018, the EU Court of Justice (CJEU) released its judgment on the case of Alheto, concerning an application for international protection lodged in a European Union (EU) member state by a distinct category of refugees, namely Palestinians registered with the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA). In dealing with the particular status accorded to such persons, the Court opined that a Palestinian who is registered with UNRWA is excluded from refugee status in the EU, so long as the protection from the UN ad hoc agency is effective, which is ascertained through a full and ex nunc examination of the facts and points of law.

On November 16, 2018, the Trial Chamber of the Extraordinary Chambers in the Courts of Cambodia (ECCC) rendered the judgment in Case 002/02 against Nuon Chea and Khieu Samphan. The full written version of the judgment was notified in Khmer, English, and French on March 28, 2019. The Chamber found Nuon and Khieu guilty of crimes against humanity, grave breaches of the Geneva Conventions, and genocide of the Vietnamese ethnic, national, and racial group. The Chamber additionally convicted Nuon of genocide of the Cham ethnic and religious group under the doctrine of superior responsibility. Both Nuon and Khieu were sentenced to life imprisonment.

On August 8, 2019, the United States Court of Appeals for the Ninth Circuit issued an opinion in Bakalian v. Central Bank of Republic of Turkey, Case No. 13-55664. In this case, the Ninth Circuit affirmed the district court's dismissal of plaintiffs’ claims seeking compensation from the Republic of Turkey and two Turkish national banks for lands that they claim were unlawfully confiscated from their ancestors during what the Court refers to as the Armenian Genocide of 1915–1923. In 2006, California adopted a statute extending the statute of limitations for claims arising out of the Armenian Genocide to December 31, 2016. Thus, the claims filed by the plaintiffs in 2010 were not time-barred under the statute; however, the panel found that since the Court had previously found the statute to be unconstitutional, no statute existed to extend the statute of limitations and therefore the claims were time-barred. The panel held that since the claims were plainly time-barred, the Court need not address legal questions posed regarding Foreign Sovereign Immunities Act jurisdiction.