The militia
The reason for the inclusion of the militia clause in the 2A has been used to justify the idea that the right to keep and bear arms belongs to the recognized militia and not individuals.
The Constitution mentions the militia 4 times. Since it is a recognized axiom that "it cannot be presumed that any clause in the Constitution is intended to be without effect" it must be accepted that these 4 instances and the instance in the 2A must comport to define the overall civilian-militia-military relationship on which the country is based.
I suggest that, while the RKBA is an individual right, it is protected within the Bill of Rights as it is, in order that a militia be maintainable with a staff of effective riflemen.
I further suggest that while the Founders were not in favor of a large standing army, they did provide for both a Navy and a smaller standing Army. These services and others along with their supporting federal infrastructures operate today as the militia was intended to. However, the foundational nature of the individual being recognized as having the right and authority to the use of arms equal to the militia (or its functioning replacement) serves not only to empower the common individual, it preserves the serviceman's view of himself as still one of "the people". That perception is fundamental and foundational to the our government as formed by the Constitution with the protections of the Bill of Rights. To deny any of that is to suggest the need to abolish both and start over.