You misunderstand what a militia is. Militias do not drill. They do not train and they do not have standing membership. The militia is made up of whoever is willing to jump out of bed in the middle of the night, grab their gun, and go fight to defend their homeland, be it against foreign invaders or against a government out of control. That's what the militia the men who wrote that amendment had belonged to was. Just guys who happened to own guns and had the balls to use them. These days there's a mistaken tendency to think of para-military groups as militia, and in a sense they are, but that's not all there is to a militia.