When, in 1791, the Second Amendment was added to the U.S. Constitution, it had a critical purpose, second perhaps only to the First. Of course, we all know that it speaks of the people's "right to bear arms", to what we might at least agree intended a "grass-roots" access to gun ownership. The Supreme court has ruled that this right applies to individuals - some argue that it was intended only for "well-regulated militia". But however you interpret it, it was definitely intended to be an alternative to, or augmentation of, the arms that might be held in the more centralized federal and state armies. Understanding the historical frailties and excesses of large governments in general, the founding fathers were not willing to leave the long-term security of the people solely in the hands of centralized authorities, for such authorities could fail - either defeated from without, or corrupted from within. By having this right to bear arms distributed broadly among the populace, to individuals or very small communities and neighborhoods, an aggressor would have to expend far more energy than simply defeating a centralized force. In keeping with the principle that our form of government is to be "by the people", and thus government only by the consent of the governed, the people themselves needed to be the last line of defense - those who would still retain what powers that might remain, should their centralized structures collapse.
Today, we have far more powerful arms than our founders could have imagined, and many argue that (for instance) powerful automatic or semi-automatic "assault rifles" are simply too dangerous to be allowed for individual private ownership. This is at least a position worthy of debate. Some would argue that in these modern times, there is no longer a threat from the collapse of government systems (into anarchy) and that devolution into government tyranny, be it foreign or domestic, would easily overwhelm a modern populace. I find both of these positions to be wishful (or defeatist) thinking. One can imagine myriad scenarios in which the collapse of centralized order into anarchy could ensue - pandemics, natural disasters, environmental destruction, debilitating warfare. The "friendly powers" of benign government we have come to trust could disappear, or be subverted into a force for mass subjugation. But unless the subjugators were bent upon global suicide, they would not wreak such broadscale destruction that there were no longer any resources left to exploit. They would not "nuke" all the landscape where food, water and arable soil exist, nor totally destroy a potential slave-labor force. And anything less than such total destruction would leave remnants of an armed populace ready to surround, to infiltrate and to fight back - unless of course that populace had already been disarmed.
Whether it be defense against roving bands of marauders following a collapse into anarchy, or against the forces of a central power turned tyrannical, our founders intended that the people themselves be equipped with reasonable means to mount a defense of that "last mile", a means to retake control of their destiny.
But rather than attempt to defend the people's "right to bear arms" directly, I would like to take a broader approach to the question of "grass-roots power". Let us put aside for a moment that the Second Amendment mentions "arms" specifically, and ask instead the broader question: What facilities should be widely distributed into the hands of the people, the individuals and small communities and neighborhoods, that would best serve as "defense in depth" of our liberty in the event of a fall into anarchy, or a tilt toward tyranny? In particular, might some combination of measures lessen somewhat our need for "commensurate firepower" in securing our long-term freedoms? I offer several below for your consideration.
1. Food Security
Our forebears would be astonished at our present access to foodstuffs, reliably available during all seasons, imported from all across the country, and from around the world. They would think "What a wonderful luxury!" And they would be right. Most of the food we eat is produced by massive and centralized farms, major corporate "agribusiness", and they do a decent job, at least, of providing volume and consistency. But if we were to tell our founders that in exchange for this mechanized cornucopia, we have increasingly knuckled-under to regulations that squeeze out the family farmers, restrict the growing of crops in residential areas, and (in the name of "food safety") prohibit the free trade and exchange of homegrown, "unlicensed" food products among individuals - I think our founders would be reaching for their guns.
When the means of your sustenance is distant and centralized, entire populations are left at the mercy of corporations, their corporate well-being, their definitions of "nutrition" and "food safety", their pricing structures, and the continued and reliable availability of transport to distribute those food products to local markets. In times of extreme stress, toward anarchy or tyranny, these highly centralized structures are key vulnerabilities to be exploited. Halt the production or delivery of food, and a populace will fall with hardly a shot fired.
I would suggest: "A well-stocked marketplace being necessary to secure health and well-being, the right of the people to local food production and trade shall not be infringed".
Note, however, that this defense-in-depth, the means to locally available food products, comes with some loss of short-term safety. It is hard enough to regulate the safety and consistency of foods produced in large, centralized facilities. It is far more difficult to provide such assurances in the trading of food produced by every home and garden. The cost of long-term distributed local food security is to accept some loss in short-term safety.
2. Communications Security
"One if by land, two if by sea." Communications is half of any successful military campaign, offense or defense. There is little that will lead more quickly to a breakdown into anarchy than the collapse of the ability to communicate. In advance of tyranny, in order to divide and conquer, an aggressor will first seek to disrupt communications among the populace, such that a coordinated defensive response cannot be mounted. Some have put forth the view that given modern weaponry (machine guns, helicopters, missiles), even a tyrannical elite that is outnumbered 100-to-1 by the general population could still prevail to subjugate a population armed with (at best) hand guns and rifles. This is open to debate, but if that aggressor can isolate us into uncoordinated islands, their likelihood of prevailing would increase substantially.
The three key strategic aspects of effective communication, critical in any military context, are confidentiality, integrity and availability (think "cia"!) Confidentiality is the ability to keep communications private or secret, such that an adversary who eavesdrops cannot learn what is being said. This is accomplished most generally through cryptography, a means of scrambling messages so that only those in possession of the right "keys" can descramble and read the message. In the early 1990s, the U.S. was sufficiently alarmed over the rise of arbitrarily strong cryptographic techniques that they outlawed the commercial export of techniques above a certain strength, hoping to thwart secret communications between the U.S. and foreign entities. Did you know that the Defense department designates cryptography as a "munition"? There are presently no restrictions upon the strength of cryptography that U.S. citizens may use personally and amongst each other. How's that for a "right to bear arms"!
Similarly, an adversary might intercept and try to "replace" a message with a false one, an attack upon the integrity of the message. Once again, a cryptographic technique known as "digital signatures" can serve to make such forgeries effectively impossible.
But most of all, a military adversary, or would-be tyrannical government would want to control the availability of communications. This is where the advent of the Internet, with its "billion channel, billion route" structures, is one of the greatest forces for freedom the world has ever known. Armed with our hand-held devices, we are collectively a "billion on-the-scene reporters", a force almost impossible to shutdown (at least, not without turning off all electricity). With the means of widespread communications distributed into the hands of individuals, the days of repressive government's ability to promote lies as truth are waning significantly. But if this access to broad-spectrum communication is to serve us in dark times, we must remain vigilant against attempts to restrict its protective features or balkanize access by region. Already, there are technologies being developed to help ensure that the Internet cannot be centrally throttled (see "FreedomBox"), where peer-to-peer forms of routing help dispense with the reliance upon centralized routers and servers.
"Effective communications being critical to the defense of a free state, the right of the people to secured messaging and an open Internet shall not be infringed."
Note, however, that the same techniques the people may use to secure their messaging against oppression are also techniques that criminals exploit to conduct their particular brands of harm. Thus once again, we must accept some loss of safety in defense of enduring freedom.