This is not a new concept. Cesare Baccaria outlined this truth in his seminal book Crimes & Punishments in 1764, in a passage that made such an impression upon Thomas Jefferson that he copied it into his daybook and quoted it at length in letters to his nephew and to James Madison:
"The laws of this nature are those which forbid to wear arms, disarming those only who are not disposed to commit the crime which the laws mean to prevent. Can it be supposed, that those who have the courage to violate the most sacred laws of humanity, and the most important of the code, will respect the less considerable and arbitrary injunctions, the violation of which is so easy, and of so little comparative importance? Does not the execution of this law deprive the subject of that personal liberty, so dear to mankind and to the wise legislator? And does it not subject the innocent to all the disagreeable circumstances that should only fall on the guilty? It certainly makes the situation of the assaulted worse and of the assailants better, and rather encourages than prevents murder, as it requires less courage to attack unarmed than armed persons."
TO WHICH I ADD AGAIN NOTE MR. JEFFERSON'S OTHER COMMENTS ON ARMS:
No free man shall ever be debarred
the use of arms.
The strongest reason for the
people to retain the right to keep and bear arms
is, as a last resort, to protect themselves
against tyranny in government.
The tree of liberty must be
refreshed from time to time with the blood of
patriots and tyrants
AND, PERHAPS, MOST IMPORTANTLY: President Thomas Jefferson's note on the interpretation of the Constitution: "On every question of construction carry ourselves back to the time when the Constitution was adopted, recollect the spirit manifested in the debates and instead of trying what meaning may be squeezed out of the text or invented against it, conform to to the probable one in which it was passed.