From the Critisim portion of the Slaughterhouse Wiki page
A spinoff ofthis case was later again heard by SCOTUS in the Butchers' Union Co. v. Crescent City Co. (1884) case, with the U.S. Supreme Court holding that Crescent City Co. did not have a contract with the state, and that revocation of the monopoly privilege was not a violation of the Contract Clause.
Harvard law professor Laurence Tribe writes that “the Slaughter-House Cases incorrectly gutted the Privileges or Immunities Clause.” Similarly, Yale law professor Akhil Amar has written “Virtually no serious modern scholar—left, right, and center—thinks that Slaughter-House is a plausible reading of the Fourteenth Amendment.”[13]
A spinoff ofthis case was later again heard by SCOTUS in the Butchers' Union Co. v. Crescent City Co. (1884) case, with the U.S. Supreme Court holding that Crescent City Co. did not have a contract with the state, and that revocation of the monopoly privilege was not a violation of the Contract Clause.