One might argue it was an activist court (which the conservatives oppose, unless of course the Supreme Court votes in their favour) that found that "A well ordered militia, necessary for the security of a free state" extended to individuals in Federal enclaves in the Supreme Court case District of Columbia v. Heller only in 2008, voting 5-4.
The court found that the Second Amendment guarantees an individual's right to possess a firearm unconnected with service in a militia, [nevermind that the first phrase of the amendment clearly states “well-ordered militia”] within a Federal Enclave (that is, the ten square mile District of Columbia, which cannot have a militia] and to use arms for traditionally lawful purposes, such as self-defense within the home. It did not find that right applied to states, narrowly tailoring the decision to the District.
The same 5-4 split in McDonald v. Chicago found only in 2010 that the same rights extended to the states, through interpretation of the XIV Amendment. Justice Breyer wrote in opposition, "In sum, the Framers did not write the Second Amendment in order to protect a private right of armed self defense. There has been, and is, no consensus that the right is, or was, 'fundamental."
(The XIV Amendment holds that all persons born in the boundaries of the USA or its territories are citizens of all the United States, passed after the Civil War to give blacks citizenship. It did not apply to Native Americans, who were not considered persons at the time. That was later settled in a case by Chief Standing Bear of the Ponca Nation v. United States, who was arrested in Omaha, Nebraska for leaving Indian Territory [now Oklahoma] without permission to bury his son, who died of smallpox, in their native land.)
The argument turned on the Slaughter-House cases (1873), that ruled the XIV Amendment did not apply to the Bill of Rights. That case came from another cause: that slaughterhouses up-river from New Orleans were polluting the river and causing cholera and other diseases in the city. New Orleans had enacted laws prohibiting slaughterhouses up-river from the city. That case found the Bill of Rights did not apply to state and local laws.
Louisiana adopted a state constitution amendment eleven years later specifically prohibiting cities from regulating the slaughterhouse industry, and cholera returned to New Orleans (as the XIV Amendment did not apply to the Bill of Rights).
The XIV Amendment guarantees of citizenship were effectively gutted by state laws, also setting the stage for Jim Crow legislation, (that is, legislation designed to prevent blacks from exercising their civil rights, such as voting). Common ploys were to only allow voting after a literacy test, which people who could document ancestry prior to the US Revolution were exempt from – that is, whites; and poll taxes, or paying a fee to vote).
That ruling held that the rights conferred by citizenship in the United States did not apply to citizenship of states. Had the 2008 court overturned the 1873 decision, the Bill of Rights would automatically be applied to all the states, which in fact today (because they did not overturn that decision) means the Bill of Rights does not apply to state and local laws, and the right to bear arms individually would automatically extend to all states, counties, and towns.
The day after the ruling, the National Rifle Association filed suits across the land to overturn state and local laws, as the Chicago ruling did not seek to overturn Slaughterhouse.
It is the same Slaughterhouse decision which protects your privilege to drive in other states, including those which prohibit my epilepsy medication. That decision essentially says states cannot apply such laws to people from out of their state (the New York DMV was specific about that to me, pointing out if I moved to New York I would lose my driving privilege but could drive in New York as long as I am a Nebraska resident duly licensed here).
The result of the 2010 case means the $300,000,000 a year National Rifle Association has launched litigation across the land, opposed by the $3,000,000 Brady Coalition's total worth, and as usual in court, the one with the most money wins, not the one with the most sound case.
The XIV Amendment argument was that Chicago’s registration laws were unduly onerous. The court found that was so, and struck them down.