When I did so, I placed threats and the actual initiation of violence against a law-abiding person (according to libertarian law) on the same plane. If it was improper to initiate violence against such a person, then it would also be illegal to threaten violence against him. Turning this around, I also maintained that if it was improper to threaten violence against an innocent person, then it would also be illegal to actually use violence against him.

But upon more mature reflection, I now see I was in error on this matter, and I thank David Gordon, who knows everything about everything, for setting me straight.

Suppose, for example, a mad bomber announced that he had an Atom Bomb located in mid-Manhattan, and was going to explode it in an hour. This is much too short a time to evacuate even a small proportion of people in that borough of New York City; there are an estimated 25 million people located there, during business hours.

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It also transpires that the police (hopefully private, but you never know) have the mad bomber's beloved three-year-old son in custody elsewhere, safely out of harm's way, at least from the nuclear device. Or, at least, they have located him, and now have him under tight surveillance. May they use violence against this toddler, to punish his father? No, no, a thousand times no, is the answer that emanates from libertarian theory. This baby is entirely innocent, and it would violate every precept of basic libertarianism to so much as lay a harsh finger on him. But, now, let me ask, seemingly, a similar question, but, actually, a very different one: Would it be compatible with libertarianism to threaten the father with his son's life if he sets off the bomb? And, here, I answer very differently than I would have previously done. As I now understand the libertarian theory (hey, I'm "growing in office" under David's tutelage), such a threat would be entirely compatible with this philosophy. Threats are very different than the actual utilization of initiatory violence, at least in this rare type of case.

Why the very strong libertarian emphasis on threats in the first place? These are crucially important since they can do the "work" of actual violence. A hoodlum points a gun at a shop-keeper and demands the contents of his cash register. The victim complies, under duress. The criminal walks out with his loot in hand, and does not, does not need to, further molest the businessman. So, if all libertarianism proscribed in its NAP was actual violence, this act of the criminal would be considered legitimate, a sorry state of affairs for our philosophy.  In fact, threats are so important that they are the only counter-example I can think of to the doctrine of free speech (that is, that you may say anything you want, on your own property, including uttering threats to blackmail, engaging in libel and slander, etc.) The exception? In virtually all case, thou mayest not utter (mere) threats of violence against innocent people, as did the mugger in this example of ours. But, as we have seen, there are exceptions to this general rule.