[Mahmoud] Abbas has neither de jure nor de facto effective control over the members of the groups (especially Hamas) that are responsible for the rocket attacks on Israel. Nor does it seem likely that he would be part of the military chain of command in a Fatah-Hamas unity government. So whatever the state of Palestine’s responsibility for the rocket attacks might be, it is extraordinarily unlikely that Abbas would ever be held individually criminally responsible for them — now or in the future.
Is any Arab-who-refers-to-himself-as-a-'Palestinian' ever responsible for anything they do?
But there is this there:
The Palestinian Authority fails all of the elements of the OTP [Office of the prosecutor of the International Criminal Court]’s “effective control” test in the context of rival governments: it does not control all of the state of Palestine, it does not enjoy the “habitual obedience of the bulk of the population,” and it does not have “a reasonable expectancy of permanence.”