People seem to have a hard time with this one, so I'll add to what you said:
"Regulated" meant to "make regular." The only similar use I know of today is "regular bowel movements." This means that you want the bowels to be functioning normally.
A well functioning militia, being necessary...
This is a big part of why we have not maintained a free state. We *need* well functioning (regulated) militias, and we don't have them, becuase we've been too lazy to maintain them.
Washington (George) was right on this one. It's time to get up off the couch and become responsible. Let's get those militias going folks.