I disagree with this approach.
The purpose of the 2A was to prevent the federal government from infringing on the right of the militia to keep and bear arms, for the dual purposes of civil and national defense including defense against government rights violations.
In order for that purpose to be served the 2A must guard the "arms" that a militia uses, guarding other "arms" that are inadequate to the task would be of no use.
Historical context, the British had seized or tried to seize arms from colonial subjects on several occasions, arms in this case being flintlock muskets and the occasional artillery piece, ie. substantially what the British Army used. They did not try and confiscate pocket knives, because while they are "arms" in a sense, they are not the arms of a militia.
So the key takeaway here is that the 2A guarantees the right to "arms" which would be used by a militia, ie. a military force. Not merely a choice of some "arms", but specifically those which a modern combat force would use.
Alright, let's point out several issues with this logic.
1. This opens the door for a subjectivist interpretation of the Second Amendment. By arguing that the Second Amendment only applies to those arms that would be relevant to the operations of a modern combat force, you're opening up the door for arguments that do things such as rationalizing bans on concealed carry and hollow-point ammunition, as modern combat forces don't carry their firearms concealed and don't use hollow-point ammunition. What you're arguing can be used to dismantle many of the legal gains that the 2A community have strived for. There's a reason why the Supreme Court spelled out in
D.C. v. Heller that the 2A consists of two clauses (the Prefatory Clause and the Operative Clause) but only one of them has any legal standing.
2. While it's true that the Founding Fathers wrote the Second Amendment with the goal of defense against government tyranny, they wrote it in such a broad and, frankly, absolutist way as to protect the possession and carrying of arms in other contexts, and they did so on purpose. Saying that the Second Amendment was written
solely for the purpose of protecting the ability of a militia to possess arms conducive to its functioning is ignorant of history and of the very writtings of the Founding Fathers. You could have a warship armed with dozens of cannons in 1789 and the government was fine with it: as a matter of fact, many of the naval engagements preceding the Mexican-American War were fought by private warships whose captains were issued Letters of Marque by the United States Congress. You brought up how the British Army came to confiscate muskets and artillery but not pocket knives, yet you didn't bring up private warships and Letters of Marque.
3. The spirit of the law can't be used as a modifier upon its text. The Second Amendment says, "the right of the people," not "the right of militias." Again, as the Supreme Court pointed out, the Prefatory Clause ("A well-regulated militia, being necessary to the security of a free state,") explained the spirit of the law but had no effect on the Operative Clause ("the right of the people to keep and bear arms, shall not be infringed.") It's that simple.
I suppose I could dig up a few other reasons as to why the idea of "the Second Amendment was solely written to protect militias" is absolutely nonsensical and historically unfounded, but this would become painstakingly boring and not worth my time. It's already painstaking that such an issue has to even be addressed in a forum where, logically, people should understand the scope of the Second Amendment and the historical context behind it.
The Second Amendment doesn't say "the right of militias to keep arms necessary for the purpose of civil and national defense."
