So-called "collateral damage" is just a euphemism for murder. You can't justify killing innocents to stop a criminal. Even if you have killed them accidentally this is, at least, manslaughter. And unless there are two moralities - one for private actors and one for state actors - then this applies to everyone, including police chiefs and five-star generals. The number of stripes on your sleeve does not justify murder or manslaughter in the pursuit of your own goals.
|"The fundamental axiom of libertarian theory is that no one may threaten or commit violence (“aggress”) against another man’s person or property. Violence may be employed only against the man who commits such violence; that is, only defensively against the aggressive violence of another. In short, no violence may be employed against a nonaggressor. Here is the fundamental rule from which can be deduced the entire corpus of libertarian theory.|
Let us set aside the more complex problem of the State for a while and consider simply relations between “private” individuals. Jones finds that he or his property is being invaded, aggressed against, by Smith. It is legitimate for Jones, as we have seen, to repel this invasion by defensive violence of his own.
... if Jones finds that his property is being stolen by Smith, he has the right to repel him and try to catch him; but he has no right to repel him by bombing a building and murdering innocent people or to catch him by spraying machine gunfire into an innocent crowd. If he does this, he is as much (or more of) a criminal aggressor as Smith is. The application to problems of war and peace is already becoming evident. For while war in the narrower sense is a conflict between States, in the broader sense we may define it as the outbreak of open violence between people or groups of people. If Smith and a group of his henchmen aggress against Jones, and Jones and his bodyguards pursue the Smith gang to their lair, we may cheer Jones on in his endeavor; and we, and others in society interested in repelling aggression, may contribute financially or personally to Jones’s cause. But Jones has no right, any more than does Smith, to aggress against anyone else in the course of his “just war”: to steal others’ property in order to finance his pursuit, to conscript others into his posse by use of violence, or to kill others in the course of his struggle to capture the Smith forces. If Jones should do any of these things, he becomes a criminal as fully as Smith, and he too becomes subject to whatever sanctions are meted out against criminality. In fact, if Smith’s crime was theft, and Jones should use conscription to catch him or should kill others in the pursuit, Jones becomes more of a criminal than Smith, for such crimes against another person as enslavement and murder are surely far worse than theft. (For while theft injures the extension of another’s personality, enslavement injures, and murder obliterates, that personality itself.)
...It is legitimate to use violence against criminals in defense of one’s rights of person and property; it is completely impermissible to violate the rights of other innocent people. War, then, is only proper when the exercise of violence is rigorously limited to the individual criminals. We may judge for ourselves how many wars or conflicts in history have met this criterion. It has often been maintained, and especially by conservatives, that the development of the horrendous modern weapons of mass murder (nuclear weapons, rockets, germ warfare, etc.) is a difference only of degree rather than kind from the simpler weapons of an earlier era. Of course, one answer to this is that when the degree is the number of human lives, the difference is a very big one. But another answer that the libertarian is particularly equipped to give is that, while the bow and arrow and even the rifle can be pinpointed, if the will be there, against actual criminals, modern nuclear weapons cannot. Here is a crucial difference in kind. Of course, the bow and arrow could be used for aggressive purposes, but it could also be pinpointed to use only against aggressors. Nuclear weapons, even “conventional” aerial bombs, cannot be. These weapons are ipso facto engines of indiscriminate mass destruction. (The only exception would be the extremely rare case where a mass of people who were all criminals inhabited a vast geographical area.) We must, therefore, conclude that the use of nuclear or similar weapons, or the threat thereof, is a sin and a crime against humanity for which there can be no justification."
And, as Rothbard notes, many weapons in the modern arsenal are inherently indiscriminate and, therefore, have no conceivable use which can be morally justified. We should foreswear the use of inherently offensive and indiscriminate weapons as bombers, NBC weapons, napalm, airburst weapons and environmental weapons (for example, defoliation). Furthermore, we should stop accepting red herrings in the justification of collateral damage by supposedly "moral" governments, such as the US government and the government of Israel. The fanaticism of a criminal does not justify killing others to stop him. We must stop accepting this barbaric morality immediately before it results in the complete breakdown of modern civilization.