The landmark 2008 U.S. Supreme Court decision in D.C. v. Heller, declaring an individual right to bear arms under the Second Amendment, may soon be eclipsed by its sequel: McDonald v. City of Chicago, set for argument March 2.

Heller limited the right to the federal enclave of the District of Columbia. McDonald may be the case that makes the right real nationwide, by applying or incorporating the right as a shield against state and local restrictions on firearms as well. The key question before the Court will be which part of the 14th Amendment should be invoked in restricting the states: the due process clause, the privileges or immunities clause or none of the above.