For the sake of argument what will happen if South Africas charges of genocide are upheld by the International Court of Justice 1 ?
At this stage, what is being sought is a provisional order asking that Israel cease its attacks against Palestinians in Gaza. For a provisional order, it is not necessary to prove that Israel is committing genocide; but rather that the acts complained of fall within the Genocide Convention.
That said, if after hearing the full case the court finds that Israel is committing genocide, this obligates not only Israel but also countries around the world to act to stop genocide. First, according to the ICJ, every UN member state must undertake to comply with a decision of the ICJ in any case to which it is a party. If they do not comply, the other party may go to the UN Security Council which may take measures to give effect to the judgment.
Beyond that, however, the crime of genocide does not just bind the party committing genocide but binds third party states too, whether or not they have ratified the Genocide Convention. What this means is that ALL states are bound and therefore must take measures to stop the genocide as well as measures not to aid Israel in committing genocide. This, of course, can take different forms including by imposing an arms embargo on Israel, boycotting and sanctioning Israel, and prosecuting war criminals.