The Ninth Circuit just issued a disappointing decision affirming the federal conviction of a Montana man for building some ponds without a Clean Water Act permit. Joseph Robertson argued that the Constitution’s Due Process Clause prevents the government from prosecuting him for violating the Act, because it is endlessly confusing as to where it applies in the first place.

Despite seeming to sympathize with Robertson at oral argument, today the Ninth Circuit disagreed. The court relied on its prior decision, River Watch v. City of Healdsburg, which interpreted where the Act applies by adopting the vaguest standard available for that question. The appellate court’s endorsement of City of Healdsburg is doubly disappointing, since that case decides the scope of federal power under the Clean Water Act based on one criterion only: what interferes the least with federal power over citizens?