To say that something may 'survive' or be at risk of being 'killed' presupposes that it was alive in the first place. Have the much-vaunted bodies of international law formed after WW2 ever indicted or punished one of their own, ie: the main western states and their economic satellites that make up its core? Has the law been applied in the same way on the merits of each case regardless of who was the perpetrator? I think the answer is obvious. Time after time the victims of US/western military hegemony pursue their cases in the international courts, get up to a certain point and then... no further. Meanwhile African dictators and Milosevic are quickly indicted for crimes that are nothing compared to, say, Vietnam, Chile, East Timor, Iraq, Yemen, Gaza.
I think Craig is a liberal internationalist at heart, so he wants international law to 'survive', and will avoid the evidence that it never existed and that it's dead as a doornail out of blind optimism, no matter how many times he is disappointed and frustrated. (At least he acknowledges that it fails to protect people in the here & now.)
More broadly, has there ever been an example of a body of law that was universally applied, regardless of the power, wealth or privilege of the accused? That's a genuine question btw, if anyone with more knowledge of the subject wants to answer. I'm inclined to think that there hasn't and that the law has always served primarily as a way to discipline the masses, ensure the transfer of wealth from the many to the few goes on unhindered, dole out extreme punishment for those who resist while letting wealthy criminals and pirates off scot-free.
IMO the example of Palestine, like so many before it, proves that there is no justice except what you are able to get for yourself. This is especially true for those at the bottom of the hierarchy, but more generally true in that justice can't really be called justice if it's not universally accessible. None are free until all are free as the saying (approximately) goes. The ICJ ruling may eventually lead to some beneficial outcome for the survivors of the Gaza massacre, but we're kidding ourselves if we think this won't be tied to the over all decline of the US empire and a serious military defeat of its main vassal state in the middle east.