The U.S. Supreme Court has agreed to review two Clean Water Act cases that could prompt yet another examination of the limits of Congress' power to protect the public. Both cases -- Carabell v. U.S. Army Corps of Engineers, 391 F.3d 704 (6th Cir. 2005), and United States v. Rapanos, 376 F.3d 629 (6th Cir. 2004) -- address whether the Clean Water Act extends federal protection over wetlands with less than simple connections to waterways that are protected under the CWA. In the course of addressing these issues, the Supreme Court could potentially address a much larger question than a straightforward interpretation of the Clean Water Act: it could speak to the scope of Congress's power under the Commerce Clause to remedy public harms. About the Cases Section 404 of the Clean Water Act requires landowners to obtain permits from the Army Corps of Engineers before dumping fill material into wetlands that are adjacent to navigable bodies of water or their tributaries. A long line of court cases has interpreted this clause broadly to cover many bodies of water that are not actually navigable but do have significance for interstate commerce. Both Carabell and Rapanos now put into question what counts as adjacent. The Michigan wetlands property in Carabell is bounded on one side by a manmade ditch with four feet wide upland berms along the banks. That ditch connects at one end to Sutherland-Oemig Drain, which empties into the Auvase Creek, which in turn empties into Lake St. Clair, a part of the Great Lakes Drainage System. The ditch connects at the other end to other ditches that ultimately empty into the Auvase Creek. The landowners, who were denied a permit to fill in the wetlands in order to build a 130-unit condominium complex, argue that their property is entirely isolated and not governed by the CWA. The landowners in Rapanos, who faced civil and criminal sanction for draining, filling, and building on protected wetlands, argue, among other things, that their parcels are several steps removed from any actual navigable bodies of water, because they are adjacent only to nonnavigable waters that themselves connect only to other nonnavigable waters that only eventually, connection after connection, reach the Great Lakes system. Accordingly, they argue, their parcels are entirely isolated and not adjacent within the meaning of the Clean Water Act. Commerce Clause Connection In each case, the U.S. Court of Appeals for the Sixth Circuit addressed the applicability of the Supreme Court's decision in Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers, 531 U.S. 159 (2001) ("SWANCC"). In SWANCC, the Supreme Court rejected the Army Corps of Engineers' CWA jurisdiction over entirely isolated, intrastate bodies of water whose only connection to interstate commerce or interstate movement of any sort was that migratory birds enjoyed them as a habitat. A minority of courts has applied the SWANCC holding to mean that Army Corps CWA jurisdiction extends only to navigable bodies of water or nonnavigable bodies that directly abut navigable waterways, but the Sixth Circuit sided with the majority trend reading SWANCC more narrowly as prohibiting only federal control over entirely isolated intrastate bodies of water. As the Seventh Circuit has observed in a similar CWA case, the question of statutory interpretation and the question of the scope of federal authority under the Commerce Clause in such a case are "interchangeable." See United States v. Gerke Excavating, 412 F.3d 804, 806 (7th Cir. 2005). When the Court probes the meaning of "adjacent," it could therefore reach the question of Congress' power under the Commerce Clause to legislate in the public interest in cases of intrastate matters that may affect interstate commerce only in the aggregate, if at all. Because the Commerce Clause is the major source of authority for federal action to protect the public interest, any constitutional inquiry raises the risk that the federal role could be circumscribed. The risk is slight in these cases, however, because the six justices who ruled recently in favor of federal drug regulation even of intrastate trade in medical marijuana are still on the bench. The two seats that are turning over -- those of Chief Justice William Rehnquist and Associate Justice Sandra Day O'Connor -- are from the minority position in Gonzales v. Raich, 125 S. Ct. 2195 (2005), the medical marijuana case reaffirming that Congress' role in protecting commerce must include the power to regulate entire classes of activity that can affect interstate commerce, even when individual instances of those activities may not have any such effect. It will be interesting to observe what new Chief Justice John Roberts will rule in these cases; nonetheless, even if he opposes the government's position, he will likely be overruled by the Raich six.