“A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.”
You may remember from grade school something called a Non-restrictive Clause, and how it differs from a Restrictive Clause. To refresh your memory, look at this definition from grammar-monster.com:
A non-restrictive clause is a clause that provides additional, non-essential information. In other words, a non-restrictive clause is not needed to identify the word it modifies, i.e., it’s just bonus information. As a non-restrictive clause is not essential to the meaning of a sentence, it is offset with commas (or some other parenthetical punctuation such as dashes).grammar-monster.com
See that comma in the 2nd Amendment at the top of the page? That makes the phrase “A well regulated militia, being necessary to the security of a free state” a classic example of a non-restrictive clause. And from the definition of such a phrase, we find that it “provides additional, non-essential information … it’s just bonus information.”
Wouldn’t it be fun to have a student use the 2nd Amendment as an example of a non-restrictive clause, just to hear the teacher’s response? Unfortunately, they probably no longer teach English grammar in school…
Rephrase as a Resolution
Alternatively, what if the 2nd Amendment had been written as a resolution? It might go something like this:
WHEREAS, the security of a free state is essential; and
WHEREAS, a well-regulated militia is necessary to ensure a free state;
NOW THEREFORE, the right of the people to keep and bear Arms, shall not be infringed.
This is even clearer and does essentially the same thing as the Amendment.