With its decision today to hear the case of McDonald v. Chicago, the Supreme Court should settle the question of whether states must recognize the Second Amendment right to keep and bear arms. In June of 2008, in District of Columbia v. Heller, the Court found, for the first time, that the federal government must recognize the Second Amendment right of individuals, quite apart from their belonging to a militia, to have an operational firearm in their home. But the decision left open the question whether states were similarly bound.

Thus, the so-called incorporation doctrine will be at issue in this case – the question of whether the Fourteenth Amendment “incorporates” the guarantees of the Bill of Rights against the states. The Bill of Rights applied originally only against the federal government. But the Fourteenth Amendment, ratified in 1868, left open the question of which rights states were bound to recognize. The modern Court has incorporated most of the rights found in the Bill of Rights, but the Second Amendment’s guarantees have yet to be incorporated.

Moreover, a question that will arise in this case is whether the Court, if it does decide that the states are bound by the Second Amendment, will reach that conclusion under the Fourteenth Amendment’s Due Process Clause or under its Privileges or Immunities Clause, which has been moribund since the infamous Slaughterhouse Cases of 1873. In its brief urging the Court to hear the McDonald petition, the Cato Institute urged the Court to revive the Privileges or Immunities Clause.