But the Security Council’s inaction has not been for lack of trying. It is because Russia, often joined by China, has obstinately propped up President Bashar al-Assad of Syria, using its veto eight times in the Council so far to block measures against him. The latest veto came on April 12, blocking a resolution introduced by the United States, France and Britain demanding that Mr. Assad cooperate with an investigation into a deadly gas attack.
With Security Council action blocked, the General Assembly, where there is no veto, voted in December to set up another body, the International, Impartial and Independent Mechanism, charged with building cases for any court that might have jurisdiction. A French judge experienced in war-crimes tribunals, Catherine Marchi-Uhel, was named its head and began work on Tuesday.
With General Assembly backing, the new body presumably has more clout than Ms. del Ponte’s, which was set up by the Human Rights Council, and its drill includes building actual cases against specific individuals. It will have access to the first panel’s voluminous findings, most of which have not been made public.
It is up to the International Criminal Court to make use of the evidence from either body. But because the court cannot take action on its own against a nonmember like Syria (the United States has also refused to join), cases must be referred by the Security Council, and Russia and China have blocked that idea.
This is deeply frustrating for victims of atrocities and for investigators. But international organizations and international justice are inherently dependent on the political will of those involved, and the Syrian conflict is an infernal tangle of political goals, ideologies and actors. Scores of armed groups are at war, backed variously by Russia, the United States, Iran, Turkey, Saudi Arabia and Qatar. The Trump administration has yet to formulate a coherent strategy for Syria, though the C.I.A. recently abandoned efforts to train some opposition groups.
Against these odds, the panel on which Ms. del Ponte worked and the new body might appear almost quixotic. Fighting in some areas of Syria is abating, in part through agreements reached between President Trump and President Vladimir Putin of Russia in July. But that is still a long way from peace, and it leaves in place those most responsible for war crimes, like Mr. Assad. The only hope for a real end to the carnage is to keep seeking a diplomatic solution.