The ICC, ICJ and the UN will do squat. They will yap a lot. Israel will continue defending itself. Trump will certainly defund both the ICC and ICJ a maybe even the UN. UNWRA is defunded already.
I would like to see Israel charge Hamas leaders an UNWRA pogrom participants with war crimes and dispense death penalties. Make sure that the HRW observes the proceedings and give them the Bin Lain treatment.