Resolution 377A(V), "Uniting for Peace," is already in effect, enabling the UN General Assembly (UNGA) to address threats to peace when the UN Security Council (UNSC) is deadlocked.
The Hague Group could propose an ES-10 resolution asserting that UNGA assumes UNSC powers in a U.S.-veto-induced deadlock, calling for voluntary military action against Israel.
If Israel or the U.S. complains about its legality, The Hague Group could refer them to the International Court of Justice (ICJ) in The Hague, where the International Criminal Court (ICC) awaits the war criminals.