The term "well regulated" was most recently described by the U.S. Supreme Court in the Heller decision as "the imposition of proper discipline and training."  If the militia is not well regulated, the purported right to keep and bear arms MUST be infringed.  A militia that is not well regulated is a detriment to society, as it undermines the security and freedom we are all meant to enjoy, such as when people are shot and killed by Merrill Field.  Cheers!