First, get yo'self a free country; and as regular readers of this column know, that's the major task faced by all of us who have even the vaguest notion of what is going on around us. Individual freedom has been, and is still being, ripped away by all levels of government and all that has to be reversed; until it is, it may fairly be asked whether there is much here worth defending.
But suppose that's been done, fully or in large part. Suppose each of us is back in substantial control of our own lives and destinies. How would such a free society best be defended from outside, foreign aggression? I admit the question is rather academic, since we're nowhere near that happy condition; but if you can join me in visualizing what a free society would be like, it's fair. Take that big leap of imagination, then, and let's look at some answers. As with many others questions, there's little comparison with today's actuality.
We'll note first that even in a free society, there would still be need for self-defense against domestic aggression; merely because government had been largely or wholly abolished, private crime would not vanish. True, the incentive to steal and do violence would be far less; no anti-drug laws would tempt the young crook with the chance of vast profits, while education would be done so well (usually at home, or elsewhere for the powerful incentive of profit) that youngsters would be awash in major, honest opportunities for gain. But despite that huge improvement, a few may still suppose that crime pays.
Against those, personal defense by means of firearms is likely to remain the best option - as it has for many centuries. In the 21st we shall perhaps see a growing market for non-lethal defense weaponry such as laser guns, to incapacitate but not to kill, and that's fine, but no police force (private or otherwise) can ever react as fast as an individual under threat so personal weapons must remain the first line of defense.
Foreign Threats
America has never been the subject of unprovoked aggression since 1776 (in 1812 the Brits harrassed US merchant ships, but that was no excuse for the government to get involved; and 129 years later Pearl Harbor was of course very heavily provoked, by FDR) so we're a bit unfamiliar with this. And if, as I propose here, our government were reduced to a size that could not provide any threat to any foreign government, the incentive to use force in revenge against our newly-free country would be far less yet.
But that's not to say no government ever will; governments everywhere are dangerous, ruthless and untrustworthy. So, we must be prepared to use force in self-defense, as a society as well as as individuals and families.
While it can't be repeated too often that the best defense is no offense, and so that the fine words of Jefferson ("peace, friendship and honest trade with all, entangling alliances with none") are as true now as always, espcially in regard to free trade, there is one incentive for foreign threat that would actually increase, as America became a free country again: envy.
Individual freedom, see, would spur a vast increase in personal wealth for everyone in society. It would start with a rapid near-doubling, as all taxes were abolished, but would go on up from there; for there is no better stimulus for economic growth than absence of restraint and the certainty of keeping whatever gain is realized. So after a very few years, Americans would be enjoying a standard of living several times greater than that in other developed countries, and that will certainly be noticed abroad.
I think it will stimulate two different reactions, as well as an increasing wish by foreign subjects of conventional governments to emigrate here. One, it will cause them to exert great pressure on those governments to do what the US one will have done - to go out of business, to get out of the way of progress and prosperity. Thus, freedom will have been "exported". Precisely as the sponsors of the Statue of Liberty hoped, Liberty will "enlighten the world."
But two, those foreign governments will see that enlightenment and (accurately) perceive a major threat to their own existence; their reaction will be to try to put out the light, to suppress dissent, to prevent their own people doing what Americans will have done. One easy way will be for them to find a pretext for making war on the newly free America. So, then, what would be our best defense? - I suggest, a dual strategy.
One, we could hire a defense consortium to provide a physical defense. That could be done by the market, just as, today, the market provides physicians and paramedics; no government involvement is needed. The consortium would no doubt do what all US governments have so far failed to do, despite confiscating trillions of our dollars in the name of "defense": erect a nuclear shelter, a means of detecting and destroying incoming missiles. Libertarian Presidential candidate Harry Browne estimated that such a task could be done for less than $100 billion a year, even today; an "insurance" premium of under $1 in $60.
And two, we would have to accept the responsibility for in-depth, individual, lethal resistance in the event that America were somehow occupied. The aggressor would presumably hope to gain something from his invasion; to grab loot and to make us slaves for his pleasure, as conquerors always do. He will be deterred only if, in advance, it is perfectly clear to him that the cost of such domination will greatly exceed the value of any loot he grabs; that his army will become so demoralized (by being shot in the back every night, and by sabotage of all its facilities) that he stands to lose more than he gains.
There's nothing new, here, and little that Americans have not already said, two hundred years ago. One of the US flags alternative to the "stars and stripes" is the picture of the snake, on the yellow background, over the words "Don't Tread on Me." If the foreign aggressor government sees that attitude in two hundred million free and well armed Americans, it will think twice, and the need for actually using violence in defense will never arise.