‘Proportionate/disproportionate’ is an utterly meaningless concept without specifying what it is that some response may or may not be in proportion to. The words are thrown around all too casually with reference to the Middle East. A little more clarity would be nice.
Here are three possibilities:
(1) Proportionate to the action that one is responding to. So if Hamas fires six poorly targeted rockets into Israeli territory, then Israel may respond in an equivalent manner.
(2) Proportionate to achieving a valid objective. So if it’s fair for Israel to want to stop Hamas’s rocket attacks, then it may respond with as much force as is necessary to do so, but no more.
(3) Proportionate to achieving a valid objective, excepting that the harm to innocents that occurs as a result of the response is not greater that the harm that would befall (other) innocents as a result of some other response. So if Israel could only stop Hamas’s attacks militarily by means that produce far more civilian casualties than continued attacks would cause, then another response should be chosen.
The first is obviously grotesque tit-for-tattery, although not many people seem to demonstrate a grasp of this (Neil D and Danny Finkelstein being exceptions). The interesting debate is between (2) and (3), pitting the overall humanitarian consequences against special responsibility for one’s own citizens and raising the distinction between deliberate and predictable yet undesired killing of civilians.