Are You Really a Constitutional Militia?

This is how it works.
The Militia Clauses of the US Constitution provide the legal basis for "the militia" under the US Constitution.  They are Article I, Section 8, Clauses 15 & 16:

• To provide for calling forth the militia to execute the laws of the union, suppress insurrections and repel invasions;
• To provide for organizing, arming, and disciplining, the militia, and for governing such part of them as may be employed in the service of the United States, reserving to the states respectively, the appointment of the officers, and the authority of training the militia according to the discipline prescribed by Congress;

I know that people like to cite to 10 U.S.C. §311 (b)(2) and say they are part of something called the "unorganised militia".  This is in spite of the fact that the term "unorganised militia" should clue them in that it might not confer any privilege.  In fact, that is downright ignorant as Article I, Section 8, Clause 16 specifically mentions "organizing".
As has been pointed out, the concept of a militia is that it is somehow a "universal" military force, although even 10 U.S.C. §311 points out the exceptions to militia duty mentioned in 10 U.S.C. §313.  There have always been people who have been exempt.
We have often seen the following quote taken out of context:

Mr. GEORGE MASON. Mr. Chairman, a worthy member has asked who are the militia , if they be not the people of this country, and if we are not to be protected from the fate of the Germans, Prussians, &c., by our representation? I ask, Who are the militia? They consist now of the whole people, except a few public officers. But I cannot say who will be the militia of the future day. If that paper on the table gets no alteration, the militia of the future day may not consist of all classes, high and low, and rich and poor; but they may be confined to the lower and middle classes of the people, granting exclusion to the higher classes of the people. If we should ever see that day, the most ignominious punishments and heavy fines may be expected. Under the present government, all ranks of people are subject to militia duty. Under such a full and equal representation as ours, there can be no ignominious punishment inflicted. But under this national, or rather consolidated government, the case will be different. The representation being so small and inadequate, they will have no fellow-feeling for the people. They may discriminate people in their own predicament, and exempt from duty all the officers and lowest creatures of the national government. If there were a more particular definition of their powers, and a clause exempting the militia from martial law except when in actual service, and from fines and punishments of an unusual nature, then we might expect that the militia would be what they are. But, if this be not the case, we cannot say how long all classes of people will be included in the militia. There will not be the same reason to expect it, because the government will be administered by different people. We know what they are now, but know not how soon they may be altered.

This quote may be far more prescient than the people who like to misrepresent it care to think, since the militia has indeed become a "select" one.  If it wasn't one at the time the Constitution was written or even before.  As I have mentioned before, Adam Smith wrote in his Wealth of Nations that militias were indeed obsolete in the age of specialisation.   But, 18th Century gentlemen liked to think they were free of standing armies.
That of course is a digression. Not too far off of one though since the Unorganised militia is something of a conceit to say that there is the possibility of universal militia service with the unorganised militia serving as a draft pool should the organised militia not have enough manpower.  For example,  Alabama Code - Section 31-2-48:

The Governor shall, when ordering out the unorganized militia, designate the number. He may order them out either by call for volunteers or draft. The unorganized militia may be attached to the several organizations of the National Guard or Naval Militia, or organized into separate divisions, brigades, regiments, battalions, companies or detachments as the Governor may deem best for service. He shall appoint the commissioned officers and warrant officers in the same manner as provided in this chapter for the appointment of officers and warrant officers of the National Guard and Naval Militia.

Indiana Code - Section 10-16-6-2: Classes of militia is more specific about how their unorganised or Sedentary militia is to be applied:

The militia shall be divided into two (2) classes, the sedentary militia and the national guard, as follows:
(1) The sedentary militia consists of all persons subject to bear arms under the Constitution of the State of Indiana who do not belong to the national guard.
(2) The national guard consists of those able-bodied citizens between the proper ages as established by this article who may be enrolled, organized, and mustered into the service of the state as provided in this article. The organized militia of the state constitutes and shall be known as the Indiana national guard.
As added by P.L.2-2003, SEC.7.
The law also makes it clear that:
(a) The Indiana national guard consists of those units:
(1) specified by:
(A) the Secretary of the Army; and
(B) the Secretary of the Air Force; and
(2) approved by the governor.

The Alabama law isn't as clear that one needs to actually be enrolled, but they are allocated as the governor deems them necessary.
As  Presser v. Illinois, 116 U.S. 252 (1886) pointed out:

It is plain from this statement of the substance of the Military Code that the two sections upon which the indictment against the plaintiff in error is based may be separated from the residue of the Code, and stand upon their own independent provisions. These sections might have been left out of the [116 U.S. 252, 264]   Military Code and put in an act by themselves, and the act thus constituted and the residue of the Military Code would have been coherent and sensible acts. If it be conceded that the entire Military Code, except these sections, is unconstitutional and invalid, for the reasons stated by the plaintiff in error, these sections are separable, and, put in an act by themselves, could not be considered as forbidden by the clauses of the constitution having reference to the militia, or to the clause forbidding the states, without the consent of congress, to keep troops in time of peace. There is no such connection between the sections which prohibit any body of men, other than the organized militia of the state and the troops of the United States, from associating as a military company and drilling with arms in any city or town of the state, and the sections which provide for the enrollment and organization of the state militia, as makes it impossible to declare one, without declaring both, invalid. ...
We think it clear that the sections under consideration, which only forbid bodies of men to associate together as military organizations, or to drill or parade with arms in cities [116 U.S. 252, 265]   and towns unless authorized by law, do not infringe the right of the people to keep and bear arms...
The right voluntarily to associate together as a military company or organization, or to drill or parade with arms, without, and independent of, an act of congress or law of the state authorizing the same, is not an attribute of national citizenship. Military organization and military drill and parade under arms are subjects especially under the control of the government of every country. They cannot be claimed as a right independent of law. Under our political system they are subject to the regulation and control of the state and federal governments, acting in due regard to their respective prerogatives and powers. The constitution and laws of the United States will be searched in vain for any support to the view that these rights are privileges and immunities of citizens of the United States independent of some specific legislation on the subject.

In other words, you may want to believe that you are part of "the" militia, but unless you are actually enrolled in a legally created and sanctioned organisation under the laws of your jurisdiction--you ain't the militia.
See also:

• Table of Selected State Militia Laws