Pervear v. The Commonwealth was a case heard by the United States Supreme Court in 1866. It concerned the constitutionality of an act passed by Virginia that allowed for a jury to be composed of less than twelve members when trying criminal cases. Pervaer argued that this violated his right to trial by jury as guaranteed under the Sixth Amendment, and sought damages from Virginia on these grounds. The court ultimately ruled against Pervaer, finding that while it did not agree with all aspects of the law, it had been enacted within state authority and thus could not be challenged in federal court. Furthermore, they found no violation of constitutional rights since juries were still being used in trials even if their size was reduced; therefore there was no infringement upon any individual's right to trial by jury as outlined in the Sixth Amendment

In Pervaer v. The Commonwealth, the Supreme Court was asked to decide whether a state law that prohibited certain individuals from engaging in the business of selling liquor was constitutional. Justice Field delivered a dissenting opinion, arguing that while states have broad powers to regulate commerce within their borders, they cannot pass laws which interfere with interstate commerce or discriminate against citizens of other states. He argued that this particular law did both by prohibiting out-of-state residents from carrying on an otherwise lawful trade and thus violated the Commerce Clause of the Constitution. Furthermore, he noted that it also discriminated against nonresidents who were not subject to similar restrictions imposed upon those living within Virginia's boundaries and therefore ran afoul of Article IV Section 2's Privileges and Immunities Clause as well as its Equal Protection Clause. In conclusion, Justice Field concluded that if such legislation is allowed to stand then no citizen would be safe from arbitrary discrimination based solely on his place of residence or origin