Indiana v. Kentucky was a Supreme Court case that was decided in 2018. The case involved a dispute between the two states over the boundary between them. Indiana claimed that the boundary was the low-water mark on the Ohio River, while Kentucky argued that it was the high-water mark. The Supreme Court ultimately sided with Indiana, ruling that the boundary was the low-water mark. The Court held that the boundary had been established by the Treaty of Paris in 1783 and that it had not been changed since then. The Court also noted that the boundary had been accepted by both states for over a century and that it was not in the public interest to change it now. The decision was a victory for Indiana, as it allowed the state to maintain control over a large portion of the Ohio River.

In the Supreme Court case of Indiana v. Kentucky, Justice Stevens wrote a dissenting opinion in which he argued that the majority's decision was wrongfully based on an outdated precedent and should be overturned. He noted that since the original ruling in 1881, there have been significant changes to both states' borders due to natural erosion and man-made alterations such as dams and reservoirs. As a result, it is no longer possible for either state to accurately measure its boundary line using only physical markers or geographical features like rivers or mountains. Furthermore, he argued that modern technology has made it much easier for surveyors to precisely determine boundaries than it was when the original ruling was issued over 130 years ago. Therefore, Justice Stevens concluded that any attempt by either state to enforce their respective claims would be arbitrary at best and should not be allowed under current law.