The test of proportionality in military response is a misnomer. The real test is minimal sufficiency.

Proportionality remains undefined: is it a rocket for a rocket, a kiloton for a kiloton, a body for a body, a percent for a percent of the population? Various measures produce very different results: Gazans fired more rockets at Israel than vice versa, but much less in terms of explosive equivalent. Palestinian terrorists attempted to kill many more Jews than vice versa, but Jews actually killed more Palestinians.
When does proportionality kick in? If it is a proper response to any violence, then Afghans and Iraqis should legally be allowed to slay millions of Americans in proportional retribution. If it is only a proper response to offense, then we arrive at the bottom of the legal battle to define offense. Were the US and Israeli wars in Afghanistan and Gaza offensive or defensive? Jurists fail to arrive at a clear-cut definition of offense because violence usually spirals: both sides commit violations of peace that fall short of war, and when war is finally launched the aggressor usually claims it to be defensive; thus the German invasion of the USSR was to German generals an act of preemption.

Whom does the proportionality apply to? When Jewish civilians are attacked, proportionality would dictate attacking Palestinian civilians rather than seeking out guerrillas. It is “a kindergarten for a kindergarten” approach. But we don’t rape a rapist’s family.

Even rabbis have traditionally resisted “an eye for an eye” proportionality as blindly brutal and reinterpreted it as compensation. The Israeli operation in Gaza, with its massive casualties and destruction, did not stop Palestinian groups from continuing rocket fire. No doubt a strictly proportional response, such as a small Israeli rocket fired at Gaza City in response to a Kassam fired on Sderot, wouldn’t have changed the terrorists’ attitudes. But neither is compensation practical: by the American standard of awards in wrongful death cases, Palestinians just don’t have enough money for Israel to impound.

Lex talionis’ compensatory nature has another aspect: reciprocal punishment must compensate for the damage. It is indeed soothing to see the offender’s eye removed. In order for the compensation to work, the reciprocal damage must be perceived as similar. But here is a trick: when the original damage occurs to a family member, the punishment is meted out to stranger, and thus cannot be perceived as similar. For damage to family members, people desire much stronger punishment of strangers. Jews are one family, the sons of Israel. Whenever foreigners hurt a Jew, simple reciprocity won’t suffice. I won’t be satisfied with taking out a single Palestinian eye for the eye of someone from my family of five million Jews here. A thousand eyes, perhaps.

Instead, the only practical approach to violence is sufficiency mitigated by the double-effect doctrine: collateral damages are permitted insofar as they remain truly collateral. The sufficiency can be anything: if the major Israel attack on Gaza failed to stop the rocket squads, then perhaps we should try the measures employed by the Egyptians, Syrians, Jordanians, and Lebanese in similar circumstances: they directed tank and artillery fire at Palestinian masses indiscriminately to pacify them temporarily.

The doctrine of sufficiency is present in the Torah: thieves were punished for two to five times the original damage in order to discourage repetition; here, clearly, efficiency tramples proportionality.

No country has ever adhered to proportionality in war, but only aimed at efficiency—that is, victory, often at any price. Since many countries are ready to pay any price for the victory, it would not be odd for Israel to exact any such price.

disproportional anti-terrorist response