Supreme Court nominee Neil Gorsuch has something in common with both Justice Clarence Thomas and with the late Justice Antonin Scalia. All three jurists are known as proponents of originalism, which is the idea that the Constitution should be interpreted according to its original meaning at the time it was adopted.

Yet despite their shared affinity for originalism, Thomas and Scalia disagreed on some fundamental questions of constitutional law. Most notably, Thomas and Scalia disagreed about whether the Supreme Court should revive and enforce the original meaning of the Privileges or Immunities Clause of the 14th Amendment. I'd like to know where Neil Gorsuch stands on this crucial divide.

Here's the deal. According to the 14th Amendment, "No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States." What are the privileges or immunities of U.S. citizens? According to Republican Congressman John Bingham of Ohio, the author of that section of the 14th Amendment, "the provisions of the Constitution guaranteeing rights, privileges, and immunities to citizens of the United States" include both those enumerated rights that are specifically spelled out somewhere in the Constitution—such as in the Bill of Rights—as well as other fundamental rights that are not enumerated in the document. Among the fundamental unenumerated rights that are secured against state abridgment, Bingham told the House of Representatives, was the "constitutional liberty…to work in an honest calling and contribute by your toil in some sort to the support of your self, to the support of your fellowmen, and to be secure in the enjoyment of the fruits of your toil."

The 14th Amendment was ratified in 1868. The Supreme Court first ruled on its meaning five years later in a dispute known as The Slaughter-House Cases. At issue was the granting of an exclusive and highly lucrative slaughterhouse monopoly to a private corporation by the Louisiana legislature. According to a number of New Orleans butchers, the monopoly law was an act of pure special interest cronyism that violated their fundamental rights to economic liberty under the 14th Amendment.

The Supreme Court disagreed, ruling 5-4 in favor of the state and its corporate beneficiaries. According to the majority opinion of Justice Samuel Miller, to view the Privileges or Immunities Clause as a guarantee of individual rights against any sort of state law or regulation would "fetter and degrade the State governments" and transform the Supreme Court into "a perpetual censor upon all legislation of the States." Miller's opinion effectively gutted the Privileges or Immunities Clause.

The principal Slaughter-House dissent was filed by Justice Stephen Field, who argued that the majority had just trashed the original meaning of the 14th Amendment. "It is to me a matter of profound regret that [the monopoly's] validity is recognized by this court," Field wrote, "for by it the right of free labor, one of the most sacred and imprescriptible rights of man, is violated." In Field's view, "the fourteenth amendment does afford such protection, and was so intended by the Congress which framed and the states which adopted it."

From the standpoint of constitutional originalism, Field had the winning argument. But he failed to carry the day at SCOTUS. Slaughter-House remains what lawyers call "good law" to this day.

Which brings us back to Clarence Thomas and Antonin Scalia.

In 2010 the Supreme Court finally had the opportunity to revisit The Slaughter-House Cases. At issue in the case of McDonald v. City of Chicago was whether the Second Amendment right to keep and bear arms applies against state and local governments via the 14th Amendment, and if it does apply, is that because the right to keep and bear arms is a privilege or immunity of U.S. citizenship, or because it is one of the liberties protected by the Due Process Clause of the 14th Amendment ("nor shall any State deprive any person of life, liberty, or property, without due process of law").

During the March 2010 oral arguments in that case, Justice Scalia openly mocked the idea of reviving the original meaning of the Privileges or Immunities Clause. "Why are you asking us to overrule 150, 140 years of prior law?" Scalia asked the libertarian lawyer Alan Gura, who was representing Otis McDonald in his gun rights fight. "Why do you undertake that burden," Scalia went on, "instead of just arguing substantive due process, which as much as I think it's wrong, I have—even I have acquiesced in it?"

It was a jaw-dropping moment. For decades Scalia had attacked the idea of using the Due Process Clause to protect substantive individual rights, denouncing it as a "judicial usurpation" and as an excuse "to render democratically adopted texts mere springboards for judicial lawmaking." Yet here was Scalia, a self-professed originalist, failing to practice what he preached in a major case dealing with the original meaning of the 14th Amendment.

Clarence Thomas kept quiet that day, as he usually does during oral arguments. But he spoke up loud and clear in his written opinion. Whereas Justice Scalia, Justice Kennedy, and Chief Justice Roberts joined the majority opinion of Justice Alito, which applied the Second Amendment against the states via substantive due process, Justice Thomas filed a lone concurrence that argued for applying the Second Amendment against the states via the Privileges or Immunities Clause and thereby restore the long lost original meaning of that provision. Thomas also strongly implied that Slaughter-House should be overruled. "The mere fact that the [Privileges or Immunities] Clause does not expressly list the rights it protects does not render it incapable of principled judicial application," Thomas wrote.

In short, Justice Thomas stood up for the original meaning of a core constitutional provision while Justice Scalia "acquiesced" to an approach that Scalia himself described as un-originalist and "wrong."

Where does Neil Gorsuch stand on the matter? Does he side with Justice Thomas and favor the judicial enforcement of the Privileges or Immunities Clause, or does he side with Justice Scalia and support maintaining the substantive due process status quo? The Senate Judiciary Committee should ask him about these fundamental constitutional issues during this week's confirmation hearings.