I don't think that military defense must be socialized any more than fire insurance on your house must be socialized. It could be argued that by insuring my house and paying the fire department to stop a fire in my own house, they would also put out a fire in yours, in order to stop your fire from hurting my house. I don't see any problem with that, and I don't think that accidental benefits of any action makes it necessary to socialize that action.
The same argument could be made regarding myriad businesses. Must healthcare be socialized because when I pay for antibiotics to cure an infection, I'm accidentally protecting my neighbors from the same infection? Shouldn't vaccinations be socialized for the same reason? If enough people are immune, the rest of the society doesn't have to pay to be vaccinated, because the disease no longer poses a threat.
If I keep my house in good order and make it prettier, and accidentally raise property values in the area, shouldn't home-restoration be socialized? After all, I can't make my house more attractive without helping my neighbors raise their property values too. In the same way, one cannot provide military protection for himself without accidentally providing protection for those around him, so I don't think that the "accidental benefit" argument for the socialization of military is any more valid than arguing that government must paint our houses.
Almost everything that we do to help ourselves ends up accidentally helping other people near us. It's the entire basis of individualism, objectivism, libertarianism, and free-market thought; that one cannot become wealthy without helping other people live a better life (without stealing or using force).
Ideally, if we are to imagine the most ideal situation for mankind and its organization, we would have no military at all, and the world would live in peace. But that isn't how human beings work. A certain percentage of human beings love to build armies and try to take over the world by force, and because of that we must have weapons to defend against those men and their armies.
If we were suddenly thrown into a world without government, we would quickly return to a world with powerful governments and powerful armies. In the ideal anarchist’s world with privatized everything, religious leaders would peacefully accumulate followers and weaponry until they became strong enough, and had a large enough army to steal from and enslave their neighbors. And this is what has happened over and over again, even in the recent past, and is ongoing in most of the world. The United States itself has within the last 200 years gone to war with multiple nations, including Mexico and Canada, and in each case was raiding a neighbor in an attempt to take over more land. The state of Texas was previously owned by Mexico. When it became a US territory in the mid-nineteenth century it was filled with native Mexicans. The United States itself is conquered land. The United States was at war with all Native American Nations and their primitive armies for hundreds of years, and the reservations we have today, scattered all across the country resemble prison camps more than anything else. The government controls every aspect of residents‘ lives, and they live in abject poverty. The Native American Nations simply lost the war, and their people were literally exterminated, with huge bounties paid by the US government for Native scalps ($5,000 per scalp or more). Millions of natives were killed in the war, and that war was no different than most other wars in the history of mankind. In each case a group of men with weapons attacks others and takes their land and anything of value they may have, and kills or enslaves them when they win.
The primitive tribes still in the world today are still doing this with spears and rocks, and even chimpanzees do it. Male raiding parties attack other groups of chimps in order to control their land. Victory means killing the men, taking the women as mates, and killing (and sometimes eating) the babies. Christianity was used to control huge armies that took over South America, killing millions of people and taking everything of value from them. I have little doubt that in a world without government, religion would easily be used to build armies and governments all over again, and anyone who wished to avoid having his wealth confiscated by the newly formed marauding armies would need a powerful army of his own, and any army powerful enough to defend you is powerful enough to enslave you.
I don’t see any way in which human beings can live in large groups without being enslaved to one army or another. Anyone trying to live outside the protection and enslavement of an army/government, even today, will eventually be forcefully enslaved or have his assets stolen by one of the existing powers. Libertarians have more than one occasion attempted to set up an ideal society on an island or boat, and as soon as they become rich enough are invariably invaded, taxed (enslaved), and controlled by the nearest government. In my view, the correct reason, and the only reason that we must have a socialized military is simply because none of us are free and it’s impossible to live without armies. The world we live in today is just a bunch of very powerful nations who have reached a cease-fire with each other. We are all slaves to one government or another, and that will be the way of the world until human beings stop trying to enslave one another and steal from each other. I think that day may not ever come, and the best we can do today is realize that if we must be a slave to an army and its leaders, we can at least convince our overlords that staying out of the private business affairs of their subjects is the best way to make everyone better off.
Imagining a society in which all men are free is an irrational fantasy. In order to avoid conquest by a neighboring army, we must have an army of our own, and again; if that army is so strong that it can defend us, it is also so strong that it owns us. We should strive not for absolute freedom, but to be enslaved by a benevolent and wise king who understands that meddling in the market is harmful to both him and his people.
