The leftists think that they can hang their hat on the opening phrase of the second amendment, "A well regulated militia being necessary for the security of a free state." They believe that "well regulated" means having lots of rules and regulations controlling the "militia", when the language of the day really meant, " being well armed and well trained." And the word "militia" meant all of the people.

The opening phrase--"A well regulated militia being necessary for the security of a free state," both sets up and explains/justifies the body of the sentence--"the right of the people to keep and bear arms shall not be infringed."

So to correctly re-phrase the second amendment in today's language, it would read:

"Since a population that is both well armed and well trained in the use of firearms is necessary to ensure a free society, the right of the people to keep and bear arms shall not be infringed."

That is what the founders actually intended everyone to understand when they wrote the second amendment, but the language has changed so that those sublteties are either not understood or are intentionally misrepresented.

Probably the latter in most cases.