In the case of Kentucky v. Indiana et al., 1929, the state of Kentucky filed a suit against Indiana and Illinois to prevent them from diverting water from Lake Michigan into the Chicago Sanitary and Ship Canal. The Supreme Court ruled in favor of Indiana and Illinois, stating that Kentucky did not have sufficient evidence to prove that it was being harmed by this diversion. Specifically, they found no proof that there would be any significant effect on the level or flow rate of Ohio River (which borders all three states) due to this action. Therefore, they concluded that Kentucky had failed to establish its right for an injunction under principles governing equitable suits between states.

The dissenting opinion in the case of Kentucky v. Indiana et al., 1929, argued that the Supreme Court did not have jurisdiction to decide on a dispute between states regarding their boundaries. The dissenters believed that such matters should be resolved through negotiation and agreement between the states involved, rather than being decided by a federal court. They also expressed concern about setting a precedent where disputes over state lines could be brought before the Supreme Court for resolution, potentially leading to an increase in litigation and conflict between states. Furthermore, they questioned whether it was appropriate or constitutional for one state to sue another in order to establish its territorial rights.