The Seat of the International Court of Justice in The Hague. (Credit: S-F/Shutterstock)

At a hearing before the Hague-based International Court of Justice, a three-lawyer Covington & Burling team accused Russia of using a seminal, post-war U.N. treaty as a legal window-dressing for its invasion of Ukraine.

At stake, they said, was not just Russia's invasion of Ukraine, but the future of one of the most-important human rights treaties adopted in the wake of the Second World War.

"The tragedy we are all watching in the streets of Kyiv, Kharkiv, Mariupol, Kherson, Volnovakha and so many other Ukrainian cities is precisely what our modern international legal system was designed to prevent," Harold Hongju Koh, the Yale law school professor who served as co-counsel, told the 15 judges on Monday. "This case has become much bigger than just Ukraine versus Russia. It has become a test of who will prevail—Russia or the post-war international legal order."

Ukraine brought the case before the Hague-based court last week, alleging that Russia had broken U.N. law by invading Ukraine and by using the 1948 U.N. treaty criminalizing genocide as justification for that military aggression.

The Covington team representing Ukraine consisted of the Washington, D.C.-based partners Marney Cheek and David Zionts and London-based partner Jonathan Gimblett. Cheek is co-chair of the firm's international arbitration practice. Koh, a legal adviser at the U.S. State Department during the Obama administration, and Paris-Nanterre University professor Jean-Marc Thouvenin served as co-counsel.

Zionts sought to establish what he described as the "factual context" behind Russia's allegations that Ukraine had committed genocide on Russian speakers in the eastern Donbass region of Ukraine since Russia's annexation of Crimea in 2014. Describing those claims as false and outrageous, he said: "Russia's claim is that a genocide has occurred under the noses of diligent UN factfinders, OSCE monitors and ICC prosecutors."

Cheek's role was to establish that the rights under the 70-year-old genocide convention that Ukraine sought to have protected by turning to the court were at the minimum plausible, which is sufficient for temporary measures to be applied in an anticipation of a later hearing on merits. 

Pointing out that Ukraine had a right under the 1948 convention not to suffer war crimes and crimes against humanity as a result of Russia's "misuse and abuse" of the treaty, she said, "Ukraine's rights are at least plausible and grounded in a possible interpretation of the Convention, which is all that the court must find at this stage for provisional measures to be appropriate." She added that Russia had "abused and misused" its rights and duties under the genocide treaty as a "legal shield" for its unlawful invasion of Ukraine.

In his comments to the court, Gimblett established the Ukrainian population's urgent need of court protection and emphasized that Russia's military operations had triggered a military, humanitarian and environmental crisis of a scope not seen on the continent since 1945. He added that these humanitarian and environmental consequences satisfied the conditions of "irreparable harm and urgency" that must exist for the Hague court to order provisional measures.

Russia, which had been scheduled to argue its case in Tuesday, did not attend the hearing and sent the court a letter saying that it had decided not to participate in the oral proceedings.

The next step is for the Hague-based court, which is the court for resolving disputes between U.N. nations, to deliver its decision on the matter. A date for that decision has not yet been announced, but it is expected in the next few weeks.

Covington has represented Ukraine in proceedings against Russia before several courts in the past.