In the case of Thomas v. Gay in 1897, the US Supreme Court dealt with a land dispute between two parties over property located in Oklahoma. The plaintiff, Thomas, claimed that he had acquired rights to the disputed land through an agreement with Native American tribes recognized by Congress. However, Gay argued that this was not valid as Congress did not have authority to grant such rights and thus his subsequent purchase of the same land from another party should be upheld. The court ruled in favor of Gay stating that only federal government has power to negotiate agreements concerning tribal lands and individuals cannot independently acquire any right or title from Native Americans without express consent from Congress.

In the dissenting opinion for Thomas v. Gay, Justice Harlan disagreed with the majority's decision to uphold a Louisiana law that allowed only state residents to harvest oysters in its waters. He argued that this law violated both the Privileges and Immunities Clause of Article IV and the Fourteenth Amendment’s Equal Protection Clause of the U.S. Constitution by discriminating against non-residents who wished to engage in an occupation lawful within Louisiana. Harlan believed that every citizen should have equal rights under federal laws regardless of their state residency status, including engaging in common occupations such as harvesting oysters from public waterways. He also pointed out inconsistencies between this case and previous rulings where similar discriminatory laws were struck down, suggesting a lack of consistency or fairness in how these constitutional protections were being applied.