I do not agree the term Militia refers to the army. Both terms were used at the time of writing to describe separate groups.
http://theweek.com/articles/629815/how-alexander-hamilton-solved-americas-gun-problem--228-years-ago
I have a copy of Barclay's English Dictionary, London, ca 1820 (King George III's Son is Regent in the line of succession in the back). In that, 'Militia' is defined as "
The Army, in it's entirety". The definition is pulled from a dusty volume.
But when I read that, it changed the way I saw the Second Amendment. As we so often do, people were arguing on the meaning of the words based on today's English usage, not the usage of the time. Words like "State", "Militia", etc. have different meaning and nuance in their usage today.
Each sovereign State had an army at the time, referred to as Militia. The term 'Army', not only designated a size of troop unit (like corps or regiment, for example), which usage persists today, but was used in some instances to delineate between a professional standing army and the armies of the various States which were on a call-up basis, commonly in the colonies referred to as 'militia', and who made their living other than by soldiering.
The common implication in modern usage is that militia are less well trained and equipped as the standing army which is a professional military.
There have been numerous convolutions over the meaning of "regulated" as well, some saying it means "trained". However, in the common usage, a regulator controls, regulations control, to regulate is the act of controlling. Keeping a military is certainly part and parcel of having a Free State (Free Country), but keeping a military from overrunning that free country from within is equally vital to keeping that State (country) free.
Whether the Federal (professional) Army was to be involved, or the State Militia (army), not only was having them for the purpose of the defense of a free state (from enemies without) vital, but being able to defend
against them if they went rogue under some ambitious commander who would use them to impose tyranny was equally important.
Like fire, an army can be a great servant, but something that can be utterly destructive if it gets out of hand.
The preponderance of arms in the hands of the People, by sheer force of numbers alone, even without martial training, was seen as the ultimate check to the misuse of power--at any level.
For that reason, the Right to Keep and Bear Arms was seen as sacrosanct and not to be infringed.
Now, re-read it.
A Well Regulated Militia being necessary to the security of a Free State, the Right of the People to Keep and Bear Arms Shall Not Be Infringed.
It makes perfect sense in the above context, and without extraordinary definitions or convolutions of logic, and continues to make sense today.
The only problem is, that by longstanding convention, the Right has been incrementally infringed upon, removing the Right from entire classes of arms (currently in common infantry use) which are rare among the populace only by virtue of long standing infringements and might otherwise not be novel or unusual to possess, and from various and sundry geographic locales, making the Right a
de facto privilege in practice.