On 23 July 2025, the International Court of Justice (ICJ) delivered its long-awaited Advisory Opinion Obligations of States in Respect of Climate Change.[1] The opinion is widely described as a “landmark”[2] because it does two things at once: (i) it clarifies what international law already requires of States on climate change, across multiple legal regimes, […]
Context in Treaty Interpretation
When addressing context in treaty interpretation, the primary point of reference is the Vienna Convention on the Law of Treaties (the “Vienna Convention”). The Vienna Convention was adopted on 23 May 1969 by the United Nations.[1] It entered into force for the original parties on 27 January 1980.[2] The Vienna Convention constitutes one of the most […]
Customary International Law and Investment Arbitration
Customary international law plays a significant role in investment arbitration disputes. Parties frequently rely on customary international law as a secondary source of law under a bilateral investment treaty (BIT) or a State contract. In some cases, arbitral tribunals have accepted a more prominent role of customary law, i.e., as a self-standing source of international […]
Ukraine’s ICJ Claim Against Russia Under the Genocide Convention
On February 26, 2022, Ukraine filed a claim against Russia before the International Court of Justice to institute proceedings in connection with the military operations commenced by the Russian Federation in Ukrainian territory on February 24.[1] The application is based on Article IX of the 1948 Genocide Convention,[2] according to which the International Court of […]
Sovereign Immunity from Jurisdiction in International Arbitration
Sovereign immunity is divided into immunity from jurisdiction and immunity from execution.[1] The conditions under which these immunities apply are of particular importance in the field of arbitration. According to the French Supreme Court, sovereignty and independence of States prevent one of them from pursuing another.[4] In other words, national judges must refrain from ruling […]