President Volodymyr Zelensky of Ukraine on Thursday delivered an address at The Hague, the seat of the International Criminal Court and a longtime symbol of international law and justice, as he pushed for a special tribunal to prosecute Russian leaders for crimes committed during the war.
“We all want to see a different Vladimir in The Hague,” Mr. Zelensky said, referring to President Vladimir V. Putin of Russia. In March, the I.C.C. issued an arrest warrant for Mr. Putin and another official on war crimes charges for their involvement in the forced removal of children from Ukraine.
Mr. Zelensky has argued for months for the establishment of a special tribunal that would run in parallel to cases pursued by the I.C.C. against Mr. Putin and others. The proposal, which he has been discussing since at least July, has been gathering steam in recent weeks, with backing from the United States, the foreign ministers of the Group of 7 industrialized nations and a host of European leaders.
The crime of aggression, the legal doctrine that would most directly hold Russian leaders to account for the invasion of Ukraine, cannot be pursued against Russia by the I.C.C. because it lacks jurisdiction.
First recognized as an international crime in the Nuremberg Trials of prominent Nazis, a crime of aggression is defined as being perpetrated by a leader — “a person in a position effectively to exercise control over or to direct the political or military action of a state” — by engaging in “the use of armed force by a state against the sovereignty, territorial integrity or political independence of another state” in violation of the United Nations Charter.
Beth Van Schaack, the State Department’s ambassador at large for global criminal justice, said last month in a hearing before the Senate Judiciary Committee that a tribunal would mark “the first prosecutions of the crime of aggression in the modern era.”
In March, the European Union said it was setting up a center for prosecuting crime of aggression cases in The Hague to coordinate the collection of evidence and investigation into Russia’s aggression in Ukraine.