The Second Amendment is quite clear.  There are two parts.  One, the militia clause requires an armed militia, which we consider the National Guard, but also covers much more.  A constitutional militia is not just the construct of gov't and we are allowed to form militias as We the People see fit.  The Second also provides for the redress of a tyrannical gov't by force of arms.  We are all required to keep and to bear arms for use in militia service--note AS 26.05.110, as every state has such statutory language.  The use of "Arms" is brilliant, in that it defines the weapon of the current time, which, if at some time in the future,  rubber bands become the  infantry weapon of choice, then 'arms'  would mean rubber bands.  The Second also covers the use of those arms for self-defense.  The Framers were brilliant men.  Freedom is bought by blood and sacrifice.  The Framers recognized this.