If the US stopped sending weapons Israel would have to stop the genocide regardless of whether they want to or not. Already even with being pumped full of pentagon weapons and fundings all they can do is bombing unarmed civilians from far away because every time they try to actually fight Hamas or Hezbollah they get fucking shredded and have to retreat within a few months and their supposedly impenetrable iron dome gets regularly bullied by Hezbollah and Ansar Allah drones, so without US help they would be doomed to fall unless they sue for peace.