"Well-regulated in the 18th century tended to be something like well-organized, well-armed, well-disciplined...It didn't mean 'regulation' in the sense that we use it now...It means the militia was in an effective shape to fight...In other words, it didn't mean the state was controlling the militia in a certain way, but rather that the militia was prepared to do its duty."

This is from https://constitutioncenter.org/images/uploads/news/CNN_Aug_1...