The main reason the Privileges or Immunities Clause is so important is because it establishes the status, citizenship, which was absolutely central to the understanding of those during reconstruction about what they were trying to achieve for the formerly enslaved population, the African American population of the South. To be a citizen of the United States means to get certain kinds of privileges, including the privilege of being treated as an equal. So in 1857, everybody understood the massive controversy about the status of the freed population was whether they are being treated as an equal and whether they are full equal citizens. Dred Scott said because they're not being treated as full equal citizens in the North, therefore they can't be citizens at all. The 14th Amendment says that conditional is true, but we're going to turn it upside down and say, "Because you are a citizen, therefore you have to be treated as an equal." I don't think the Privileges or Immunities Clause has been taken for granted. I think it's a specter that has been haunting Constitutional Law ever since 1873. So if you remember the adage that I use over and over again in constitutional law, nothing ever dies. You might think you may have been told that the Privileges or Immunities Clause was killed on April 14th, 1873. And in a certain sense, it was. The Court in 1873 said, "Well, the privileges of citizens of the United States, that's distinctively national privileges." That's things like the right to be protected by the federal government when you're in France. Well, that's a very small set. Not the kind of thing that any state would interfere with. Not the kind of thing that it was of particular concern to the freedman at the time. But 11 years later, after the Slaughterhouse Cases in 1873, the slaughtering monopoly came back to the Court. And in a decision in 1884, they said Louisiana is allowed to revoke the slaughtering monopoly. But two concurrences by Justices Bradley and Field actually said, "We think we were right 11 years ago about the Privileges or Immunities Clause meaning something. And we thought that then, and we still think that today." Those concurrences, Justice Bradley's concurrence, saying that things like the right to be a butcher are still privileges of citizens of the United States, that concurrence was the key precedent that the court relied on 13 years after that in Allgeyer versus Louisiana, which is the key precedent on which the court relied on in Lochner versus United States in 1905. So the ghost of the Slaughterhouse dissents is haunting Constitutional Law because it lies under the floorboards of our key substantive due process precedence. So if you look at a case like Obergefell versus Hodges, what is it relying on? Well, Obergefell in 2015 is relying on Roe from 1973. Roe in '73 is relying on Griswold from '65. Griswold in '65 is relying on Meyer versus Nebraska from 1923. Meyer is relying, in 1923, on Lochner from 1905. Lochner in 1905 is relying on Agee from 1897, which is relying on the Slaughterhouse two concurrences from 1884, which is all relying on the Slaughterhouse cases dissent.