The threat

A similar argument clairfying the "proportionality" issue under just war theory is posted by Kenneth Anderson, a law professor at the American University Law School. I think that the one thing I would add is that the underlying threat that Israel is responding to is not just a stream of hostage takings and missile firings themselves. It is allowing a terrorist enemy to show the world that it can do such things with impunity. If it does so successfully, it will lead not only to more hostage takings and missiles, it will embolden others and encourage the idea that Israel is weak. The enemy wants to destroy their state. Like a mafioso or anyone whose survival depends on the perceptions of others of thier own prowess, the perception of weakness is more dangerous than provocations that lead to that perception.