Michael McConnell has a very interesting article just out in the University of Illinois Law Review called, Ways to Think About Unenumerated Rights (one of several papers considering Akhil Amar’s book, The Unwritten Constitution). After criticizing the Supreme Court’s substantive due process jurisprudence as a historically unsupportable source of unenumerated rights, Michael goes on to note two other possible sources of unenumerated rights in the Constitution: the Ninth Amendment and the Privileges or Immunities Clause of the 14th Amendment.

In both cases, however, the nature and scope of unenumerated rights are substantially limited. The Ninth Amendment states that the enumeration of rights in the Constitution “shall not be construed to deny or disparage others retained by the people.” In contrast to theorists who read the clause to protect a whole suite of positive rights, Michael sees it as protecting negative rights–freedoms from interference–which the people may give up in exchange for more attractive protections from the government. These negative rights are, therefore, violable: “the people decide which of these rights to relinquish in exchange for the protections and benefits of civil society.” All that the Ninth Amendment is doing is not “denying or disparaging” those “retained” rights; it is not enshrining them or giving them the stature of enumerated rights. These “natural” rights control unless “legislative abrogation is clear.”

Michael’s second example of unenumerated rights in the Constitution is even more interesting: the Privileges or Immunities Clause of the Fourteenth Amendment (“No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States….”), which was rendered toothless and superfluous by the Slaughterhouse Cases.

But if one were to give the Clause content, there are two options–an enumerated and an unenumerated possibility. The enumerated possibility is to say that the content of the Privileges or Immunities Clause is the Bill of Rights, now applied against the states. This is the familiar and highly plausible position that the Privileges or Immunities Clause is the true vehicle for incorporation of the Bill of Rights against the states (see, e.g., some of the work of Kurt Lash and Amar himself).

The unenumerated possibility is to say that the content of the Privileges or Immunities Clause mirrors the content of the Privileges and Immunities Clause of Article IV. Some of that content was fleshed out by Justice Bushrod Washington in the federal circuit case of Corfield v. Coryell (1823) (my former constitutional law students will remember this as the “clamming case”). There, Justice Washington wrote that the P&I Clause refers to those unenumerated rights “which are, in their nature, fundamental; which belong, of right, to the citizens of all free governments; and which have, at all times, been enjoyed by the citizens of the several states which compose this Union, from the time of their becoming free, independent, and sovereign.”

But how would one know which sort of unenumerated rights fell into this group? If the Ninth Amendment’s limits are set by the concept of negative liberty, what are the limits on unenumerated rights under this theory of the Privileges or Immunities Clause? The answer is that only those rights that are long-standing, traditionally and broadly recognized, and with deep historical roots qualify:

Taken in a broad spirit, this might be thought to authorize judges to identify those rights that are firmly embedded on our laws and traditions, both as a matter of longevity and as a matter of national consensus—as the Court held in Washington v Glucksberg. This interpretation draws strength from the overall thrust of the Fourteenth Amendment as a nationalization of the content of rights. In effect, when a particular right has been recognized by a large majority of states for a long period of time, judges are empowered to treat it as a “privilege or immunity” of national citizenship and enforce it against outlier states that may depart from that consensus. Rights become national by virtue of time, consensus, and experience. This could provide a stronger explanation for Griswold [v. Connecticut]: because every other state recognized the right of married couples to use contraceptives, and had for many decades, the Court was within its authority to declare Connecticut’s law invalid.

Note, though, that this approach does not give courts authority to engage in contentious moral reasoning or to elevate one side in a reasonable disagreement to constitutional victor. It provides no support for Roe v. Wade, for example. Enforcing national consensus is not an exercise in moral philosophy but of determining the weight of national practice. It is a nationalistic and traditionalist inquiry, not a moralistic or progressive one.