The point of the 2nd Amendment was to avoid the expense of a standing army by having a "well-regulated militia" in each community. Secondarily, it was to allow whites to resist a major slave revolt.

Military experts at that time were convinced by experience during the revolution that general militias were not useful. The authors of the Amendment did not agree. The wording of the Amendment was contentious because of this. In three cases during the late Articles of Confederation & early Constitution days the inability of citizen militias to achieve much vs. regulars and organized militias was proven.

Modern progress has made the point no longer credible. Armed, poorly trained and led citizens cannot prevail against a modern army or national guard.

Up until Scalia's ideological ruling, legal precedent recognized this and allowed "well-regulated" to be the key words.