Full Definition of MILITIA
a : a part of the organized armed forces of a country liable to call only in emergency
b : a body of citizens organized for military service
: the whole body of able-bodied male citizens declared by law as being subject to call to military service
(Source: Merriam-Webster’s Dictionary)
Please note that “the whole body of able-bodies male citizens declared by law as being subject to call to military service.” If you have ever had a draft card, this makes you eligible to have a gun under their militia excuse. But lets take things a step further.
Let’s look at an excerpt of Federalist Papers #29
“if circumstances should at any time oblige the government to form an army of any magnitude that army can never be formidable to the liberties of the people while there is a large body of citizens, little, if at all, inferior to them in discipline and the use of arms, who stand ready to defend their own rights and those of their fellow-citizens. This appears to me the only substitute that can be devised for a standing army, and the best possible security against it, if it should exist.”
So the founding fathers recognized that any who stand ready to defend their own rights and their fellow citizens. It also recognizes that it is a counter to a standing army should there ever be one (as we have now) if that army was to be used against the people.