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.
This is probably the most debated phrases in the U.S. Costitution. Its brevity belies it’s hidden truths as understood by its author. But to really understand its meaning one must step back in time to around 1789 when the Bill of Rights was presented to Congress by James Madison its author. The War of Independence had ended a decade earlier but people still remembered why they had fought so hard and risked it all to fight the British Crown and Empire. Loyalists still existed who wanted to form another monarchy. And there was the ever present fear that the British would take back the rebel colonies.
The nation was still relatively poor and could not afford a large standing army. So each state had to have a well trained and organized volunteer contingency militia, whose units did exercise on a regular basis to work well together as a unit with a chain of command as all this was stipulated in the regulations, that was ready to protect both state and nation when called upon. But that in itself did not warrant an amendment to the Constitution.
The Federalist Papers, specifically #46, contains the missing links to the rest of the story. What is not apparent to us was that some state legislators at that time feared that a president might get the idea to become a monarchy by taking over the states by trickery such as taking away the militia’s arms with a promise of new ones. Anyone that served in the military also knows that there are regulations for every aspect of behavior in the military.
The 2nd Amendment states that ”A well regulated Militia,” A well organized state militia with regulations, ”being necessary to the security of a free State,” that is needed to protect the security of each state and the nation, “the right of the people to keep and bear Arms,” has the right of its member to own and use their own weapon, “shall not be infringed.” which the government can not take away.
So putting it all together:
A well organized state militia with regulations, that is needed to protect the security of each state and the nation, has the right of its member to own and use their own weapons, which the government can not take away. [For fear that the Federal government could take their weapons leaving the states vulnerable to a federal takeover.]
This was put into the Constitution to appease many states legislators who might be concerned that the Federal government could threaten the security of the states by taking away their arms. They also wanted to make sure that each state had a well organized and trained militia able to defend the country at a moments notice. Every word of this very brief and at that time meaningful Amendment had an essential purpose. No words were wasted. Its meaning at the time of its introduction was very clear to those who ratified the 2nd Amendment and the Bill of Rights.
It all makes perfect sense when you look at it from its historical perspective (Federalist Paper #46) what James Madison intended in 1789 contrasted to our contemporary perspectives, traditions, and desired interpreted into the 2nd Amendment today.