From The Atlantic:

It has been 11 years since a 5–4 majority, in District of Columbia v. Heller, announced that the Second Amendment protects an individual right to possess handguns in the home for purposes of self-defense. It has been nine years since the same majority held in McDonald v. City of Chicago that an identical handgun-possession right is “incorporated” by the due-process clause of the Fourteenth Amendment (which means it applies to states—and cities—as well as to the federal government). The Court in Heller indicated that it was deciding only a narrow question. Justice Antonin Scalia’s opinion cautioned that “nothing in our opinion should be taken to cast doubt on longstanding prohibitions on the possession of firearms by felons and the mentally ill, or laws forbidding the carrying of firearms in sensitive places such as schools and government buildings, or laws imposing conditions and qualifications on the commercial sale of arms.”