Many noncombatants have died in Gaza to date. Hamas, not Israel, bears responsibility for this tragedy. Its fighters hide in underground tunnels below human shields. Israel’s actions inevitably will cause extensive civilian casualties, but under the circumstances, those casualties are not excessive to the legitimate military advantage Israel stands to gain, which is the real meaning of the often-misunderstood principle of proportionality.

To put Israel's actions in context, the aggregate numbers are useful. Gazan health officials, who report to Hamas, estimated in mid-January that 25,000 Gazan civilians have died from war-related causes since October 7. The IDF asserted at about the same time that it had killed 9,000 Hamas fighters. Taking these numbers at face value, Israel’s response to Hamas has yielded roughly a 1.8:1 noncombatant-to-combatant fatality ratio. This rate is significantly lower than that of other asymmetric battles, such as the 2016 Battle of Mosul, in which Iraq and allied forces defeated the forces of the Islamic State. In fact, according to the UN, the average rate for wars is usually nine noncombatants killed for every one combatant. These facts speak to an ethical accomplishment: the fourth-side-open principle has saved many lives. They also highlight Israel's relative caution in its response to Hamas, which its critics refuse to acknowledge.