The reason the Founding Fathers were so fond of militias is that militias played a big part in winning the Revolutionary War. They could form, attack and disperse before the redcoats could bring reinforcements to the scene. This was a great way to attack things like supply trains, which is a big part of the reason Burgoyne lost at Saratoga. As he moved further south from Canada and his supply lines got longer and longer, they became more vulnerable to militia attack.

(That stuff about him not getting his orders because someone in London was going on vacation is bullshit–sorry, G.B. Shaw.)

Of course, anyone who can’t think of a dozen reasons why this is no longer applicable in America today isn’t trying. “Militias” are even more anachronistic than muskets.