Concern has been voiced in some quarters that Israel should not be punishing Lebanon for the acts of Hezbollah, because Lebanon's army has not attacked Israel and it is unclear whether Lebanon has the ability to disarm or otherwise restrain Hezbollah. (There is also, however, doubt whether Lebanon has the will to do so.) In other words, Israel's conduct is being criticized as an exercise of collective punishment (likewise its military measures in Gaza), which involves punishing a collective for the act of an individual member, even if some or all of the other members of the collective bear no responsibility for the act. Israel has responded that since Hezbollah is a part of the Lebanese government, its acts are the Lebanese government's acts. That may be, but is to one side of the issue of the appropriateness of collective punishment. Israel has also defended its actions as targeted exclusively on Hezbollah, with any harms to Lebanese who are not part of Hezbollah's armed wing being inevitable accidents of war.
Without taking sides, but assuming for the sake of argument that Israel is engaged, in part anyway, in the deliberate infliction of collective punishment, I want to discuss the economics of collective punishment, which is a conventional legal tool that is efficient in many of its applications. An important modern example is the employer's liability for injuries resulting from acts by its employees within the scope of their duties. The employer may have exercised due care in the selection, training, assigning, monitoring, and disciplining of the employee who caused the accident, but if the employee was at fault and therefore is liable to the victim, the employer is also liable no matter how faultless its behavior. And usually it is the employer that ends up paying the entire judgment in the suit by the victim because the employee is more often that not judgment-proof. The law allows the employer to seek indemnity from the employee for any judgment the employer is required to pay the victim of the employee's tort, because the employee is the primary wrongdoer. But the judgment-proof problem renders the employer's right of indemnity of little or no value in most cases.
Another important example of collective punishment in law is the rule that all members of a conspiracy are criminally liable for the crimes committed by any member within the scope of the conspiracy, provided it was forseseeable. So if one member of a drug gang beats up a defaulting customer, the other members are apt to be guilty of assault and battery as well even though they had nothing to do with the beating. A related rule, the felony-murder rule, makes a criminal guilty of first-degree murder if a killing occurs in the course of his crime, even if the killing is by someone else and he did not authorize or even expect it--as in the case where a policeman in the course of trying to thwart the crime accidentally kills a bystander.
The theory behind these rules--the theory behind collective punishment in general--is that someone other than the actual perpetrator of a wrongful act may have more information that he could, if motivated, use to prevent the act than the government has. The employer may have been faultless in the particular case, but knowing that it is liable anyway will give it a strong incentive to exert control over its employees to prevent accidents--even by such indirect measures as reducing its work force by substituting robots or other mechanical devices for fallible human workers. Similarly, conspirators have an incentive to police their members to avoid getting themselves into unnecessary trouble; and the perpetrators of a bank robbery, for example, have an incentive to avoid being armed or provoking bank guards or police.
Collective punishment can properly be criticized when the cost of punishment to the innocent members of the collective is disproportionate to the benefits. This would be true if the government executed the family members of murderers. Such a measure would create powerful incentives for family members to monitor each other's behavior, and the murder rate would drop. Or would it? The law would deter the formation of families; and it might even induce families to murder members whom they thought likely to commit murders, since the family might be better able to conceal a murder within the family than the family member who was murdered would have been able to conceal his own murders. In addition, even if the family-responsibility law was effective in reducing the murder rate, the rate of killing might rise; for suppose there were 10 percent fewer murders but for every murder that did occur an average of two family members would be executed.
The example, while extreme, illustrates the essential point about collective punishment: that it is an extremely costly method of punishment, because several or many people are punished for the wrongful act of one. For example, if the cost of punishment to a person punished is X, then if he is a member of a group of ten, all of whom are punished collectively for his act, the punishment cost is 10X rather than X. So collective punishment is properly regarded as highly exceptional. It is most likely to be optimal if either the collective punishment is very mild or the cost to the punisher of failing to prevent the wrongful act is very great, and in either case if in addition the alternative of individual punishment is inadequate. The first case is illustrated by mild collective punishment of children. It includes things like a parent's punishing both his squabbling children because he cannot figure out which one was at fault, or a teacher's keeping the entire class after school because he cannot determine which child threw a spitball at him. These are easy cases because the innocent member or members of the collectively punished group have the necessary information, and ability to act effectively on it, for preventing the misbehavior; they can do so at much lower cost than the punisher because the punisher cannot readily obtain the information necessary to identify the actual wrongdoer; yet the costs to the group of the punishment are slight.
The second case--optimal collective punishment when the cost of failing to prevent the wrongful is great--may be illustrated by Israel's policy of demolishing the houses of the families of suicide bombers. The suicide bomber himself is not deterrable, the harm he does is great, and the punishment method, while severe, is mild relative to the harm that a successful suicide bomber can inflict.
Because warfare is inherently indiscriminate, innocent persons whose only connection to the fighting is that they live in the combat zone are unavoidably "punished," but this is not collective punishment as a deliberate policy. For one thing, those persons will usually have no ability to restrain the combatants on their side. As for the conflict in Lebanon, however, a nation is undoubtedly responsible for predatory acts committed against another nation by groups operating openly on the nation's territory. That responsibility is an example of the kind of collective responsibility that warrants collective punishment for its breach, as in the somewhat parallel case of the employer's liability for the torts of its employees when they are committed within the scope of employment. But how do you "punish" a nation? The nation is the collective of its citizens. Punishing the nation means punishing its citizens even if there is nothing they can do or could ever have done to to prevent the actions for which they are being held responsible. Assessment of the reasonableness of the punisher‚Äôs course of action would then depend on such factors as the alternatives open to the punisher, the amount of damage inflicted by the group that the collectively punished population failed to prevent, the amount of damage that collective punishment inflicts on that population, and the likelihood that the punishment will succeed in getting the punished nation to take effective steps to prevent similar attacks by the rogue group in the future. The last point is vital because it is extremely difficult for one nation to prevent an attack mounted by a terrorist group from the territory of a nation that has acted as the group's willing or unwilling host. That is why that nation is responsible for restraining the group and why, therefore, it may be a proper candidate for collective punishment.
A final point. I said earlier that a law imposing capital punishment on family members who failed to prevent one of their members from committing a murder would discourage family formation. In other words, collective punishment tends to cause defection from the group. This may be in the punisher's interest: if Lebanese flee southern Lebanon so as not to be "collectively punished" for the acts of Hezbollah, Israel will have a freer hand in dealing with Hezbollah there.