The migratory bird rule, adopted by the United States Army Corps of Engineers and the Environmental Protection Agency (EPA) asserted that the Clean Water Act (CWA) covers regulation of isolated waters "which are or would be used as habitat by... migratory birds that cross state lines."
v. Army Corps of Engineers threw out the "Migratory Bird Rule,"[3] A case that pitted a consortium of towns around Chicago, Illinois over isolated wetlands, inhabited or visited by over 100 migratory bird species, against the US Army Corps of Engineers.
For the previous 15 years lower courts had sustained the rule in favor of migratory birds, siding with the Army Corps.
[4] The Supreme Court held that neither the Corps nor the EPA can exert CWA jurisdiction over isolated, intrastate, non-navigable waters, where the sole basis for asserting CWA jurisdiction rests on the three factors listed under the Migratory Bird Rule, above.
[1] At least one state reacted to the new Supreme Court ruling by restoring isolated wetlands protection: the 2001 Wisconsin Act 6 is the first of its kind nationwide to restore wetlands regulation to the state after federal authority had been revoked.