In a muddled 5-to-4 decision on federal regulation of private wetlands, the Supreme Court last week suggested the Army Corps of Engineers had vastly exceeded the authority granted in the Clean Water Act to protect “navigable waters.” Over time, the Corps has claimed regulatory authority over isolated wetlands miles from any stream. Small landowners have been fined and jailed. Justice Scalia stressed the Corps’ “expansive interpretation” of the CWA. Although the court’s opinion was anything but clear, it could force the Corps into finally deciding that “navigable waters” do not include a rancher’s stock pond.