The U.S. Supreme Court case Michigan v. Ohio in 1972 revolved around a territorial dispute between the two states regarding their shared border along Lake Erie and Toledo Harbor. The controversy arose due to ambiguities in an 1836 congressional resolution that established the boundary line, which was further complicated by changes in the coastline over time due to natural forces and human activities such as dredging. Michigan argued for a more southerly boundary based on historical maps while Ohio advocated for a northerly one based on modern charts reflecting current conditions of the harbor area. The Supreme Court appointed a Special Master to gather evidence and make recommendations. After reviewing his report, which favored Ohio's position, the court ruled unanimously (9-0) against Michigan's claim, thereby affirming Ohio’s jurisdiction over most of Toledo Harbor including Turtle Island - an island located within it. This decision effectively ended nearly 140 years of intermittent disputes between these two states about this portion of their common border.

In the dissenting opinion for Michigan v. Ohio, 1972, it was argued that the majority's decision to grant Ohio jurisdiction over Turtle Island in Lake Erie contradicted previous rulings and established principles of boundary determination. The dissenters believed that historical evidence clearly showed Michigan had exercised jurisdiction over the island since its statehood without any objections from Ohio until recent years. They also pointed out inconsistencies in applying different rules for determining land and water boundaries within a single body of water - Lake Erie. Furthermore, they disagreed with the majority's reliance on an ambiguous phrase in a nearly two-century-old Congressional Act to justify their ruling instead of considering more reliable sources such as maps or official documents from both states' early history which consistently placed Turtle Island under Michigan’s control.