Judge Posner issued U.S. v. Gerke Excavating, Inc. yesterday where he argued that it doesn't matter whether waterways are navigable or not, Congress still has the power to regulate them based on the Commerce Clause. Judge Posner analogized to prior decisions that have allowed for the regulation of groundwater, because pollution might affect the groundwater, which might affect agriculture, and agriculture involves goods traded in interstate commerce.

I think it is clear that Congress has the power to regulate navigable waters as well as tributaries when the regulation deals with an activity that could substantially affect those channels of interstate commerce, but it is not clear to me that the referenced groundwater decisions or any arguments for regulating waters that aren't navigable and that would not affect navigability of interstate waters is necessarily Constitutional.

The Posner argument that pollution affects water, which affects agriculture, which involves goods traded in interstate commerce seems closer to the reasoning that was rejected in Lopez and Morrison (and embraced by Justice Breyer's dissents in those opinions) than it does to the Wickard v. Fillburn opinion, which was recently reaffirmed in Gonzales v. Raich.

Lopez and Morrison rejected the argument that it was sufficient for Constitutional purposes that guns in schools or violence to women could affect productivity which could affect goods that trade in commerce. The indirect chain of events was not sufficient to meet the Commerce Clause test. But Raich involved regulating a good that wasn't trading in commerce (home-grown, personal use, medical marijuana) yet had a perfect substitute that was trading in commerce (other marijuana). The impact of regulating (or not regulating) the first type of marijuana directly impacted the commercial regulation of the second type of marijuana. (As Justice Scalia might have put it, it was necessary and proper to regulate home-grown, personal use, medical marijuana in order to regulate marijuana in general). If Raich didn't completely knock Lopez and Morrison down to their facts, which I do not believe it did, the regulation of groundwater and non-navigable waterways that don't directly impact naviagable waterways seems like an area that could remain beyond Congressional Commerce Clause power to regulate.