The U.S. Supreme Court case Wisconsin et al. v. Illinois et al., 1929, revolved around a dispute over water diversion from Lake Michigan to the Mississippi River basin by the Sanitary District of Chicago (now known as The Metropolitan Water Reclamation District). Several states including Wisconsin, Michigan, and New York filed suit against Illinois and the sanitary district arguing that this diversion lowered lake levels which negatively impacted navigation and commerce in these states. They sought an injunction to limit or halt this diversion altogether. In its decision, the court acknowledged that while there was indeed some harm caused by this action on part of Illinois' sanitary district, it wasn't significant enough to warrant an injunction as requested by plaintiff states due to lack of substantial evidence proving severe damage or interference with interstate commerce rights. However, recognizing potential future disputes arising out of similar situations where one state's actions could potentially harm another's interests; especially concerning shared natural resources like rivers & lakes - The court suggested Congress should enact legislation providing clear guidelines for such scenarios thereby avoiding unnecessary litigation between States.

In the dissenting opinion for Wisconsin et al. v. Illinois et al., it was argued that the diversion of water from Lake Michigan by Chicago, while having some negative effects on other states around the Great Lakes, also had significant benefits in terms of improving sanitation and navigation. The dissenters believed that these benefits outweighed any potential harm caused to neighboring states and therefore did not constitute an unreasonable use of interstate waters as claimed by plaintiffs. They further contended that this case should be resolved through negotiation between affected states rather than judicial intervention, emphasizing cooperative federalism over litigation in resolving disputes involving shared natural resources.