Why the 2nd Amendment may no longer be revelent to the Federal Government

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Army Reserve National Guard units do perform some of the same functions that state militias used to, but I'm pretty sure the ARNG is not officially considered a militia. Can you cite a source that it is?

I think you'll find that "the people" are considered a reserve (unofficial and unorganized) militia. The 2nd Amendment addresses only "well regulated" (official and organized) militias.

The 2nd Amendment says no such thing. To the contrary, it says that the purpose of the militia is security of the state. And IIRC, elsewhere in the Constitution armed rebellion is made unlawful.

"The people" indeed refers to the people as a whole, with those capable of bearing arms comprising the unorganized "militia".

"Well regulated" in the parlance of the day means competent and trained. I.E. A well "regulated" timepiece/clock-- accurate and reliable. Not "controlled by federal regulations (laws)". The true meaning is that "the people" are not to be forbade, limited, or denied access to arms, as that would decrease their ability to be competent (and respond to threats) with them.

The Federalist papers leave absolutely no wiggle room in what their intent was. "We" ("the people") are not to be debarred, fettered, forbade, limited, etc... the right to keep and bear arms. Our right to keep and bear arms is not to be infringed. Period.