Those who expect the Supreme Court to rethink and perhaps overturn the Slaughterhouse cases in McDonald v. City of Chicago often look to the scope of the cert grant to justify that prediction. The Justices could have granted cert only on the question of whether the Due Process clause incorporates the Second Amendment. But they didn’t. Instead, the Justices granted on both Due Process and Privileges or Immunities. Given that the Slaughterhouse cases seem to foreclose a ruling that the Privileges or Immunities clause incorporates the Second Amendment, doesn’t the broad cert grant clearly show that Slaughterhouse is in play?
We don’t know what the Justices were thinking with any certainty. At the same time, I think there are two plausible reasons why the Court would grant cert on both issues without intending to reopen the debate over Slaughterhouse. The first is mathematical and the second is historical.
1) The first reason is the need to get to five. When the Justices met to decide whether to grant cert in McDonald, they wouldn’t know how the votes would ultimately play out. Most importantly, they wouldn’t know if there would be five votes to incorporate under Due Process. The Justices would be aware of the possibility that there might be four votes in favor of incorporation by Due Process but against incorporation by Privileges or Immunities (presumably CJR, AS, SA, & AMK); one vote against incorporation by Due Process but in favor of incorporation by Privileges or Immunities (CT); and four votes against incorporation under either theory (presumably JPS, SGB, RBG, and SS).
If that’s the case — and we don’t know it is, only that it’s a possibility — it would be important to grant on both issues at once. If the Court granted only on Due Process and left Privileges or Immunities for another day, the Court would end up with five votes against incorporation and four in favor (presumably with a concurrence by Justice Thomas saying that he might or would reach a different result if the Privileges or Immunities issue were before the Court). Then the Justices would have the problem of how to get the P or I issue before the Court again, which would ultimately lead to an 8-1 decision against incorporation by P or I. The result would be two Supreme Court opinions holding that the Second Amendment is not incorporated despite five Justices favoring incorporation.
Given the possibility that the Justices might need both clauses to get to five, it makes sense to address both clauses at once.
2) A second plausible reason to grant on both issues is historical. The Supreme Court’s 19th Century precedents ruling that the Second Amendment does not apply to the states are based primarily on the Privileges or Immunities clause. See Presser v. Illinois, 116 U.S. 252 (1886); United States v. Cruikshank, 92 U.S. 542 (1875). At the time, the Privileges or Immunities Clause was considered the only plausible candidate for applying the Bill of Rights to the states: A decision ruling that the Privileges or Immunities clause did not incorporate the Second Amendment was considered a ruling that the the Second Amendment did not apply to the states period. Note how Justice Scalia described the present effect of those 19th Century privileges or immunities cases last year in DC v. Heller, with emphasis added:
With respect to Cruikshank’s continuing validity on incorporation, a question not presented by this case, we note that Cruikshank also said that the First Amendment did not apply against the States and did not engage in the sort of Fourteenth Amendment inquiry required by our later cases. Our later decisions in Presser v. Illinois, 116 U. S. 252, 265 (1886) and Miller v. Texas, 153 U. S. 535, 538 (1894) , reaffirmed that the Second Amendment applies only to the Federal Government.
If you’re granting cert to determine whether the Second Amendment applies to the states, and answering “yes” would effectively overturn Cruikshank and Presser, it would be a bit unusual to grant cert in a way that would make the precedents to be overturned outside the cert grant. Given the shifting roles of the two clauses in the many decades since those precedents were handed down, it makes sense to look generally at whether the Fourteenth Amendment incorporates the Second Amendment rather than whether just one clause does.
To be clear, I’m not saying that either or both of these possibilities are clearly correct. As I said, we just don’t know. But I think either of these explanations could explain why the Court granted on both issues rather than limiting the cert grant to just the Due Process clause.