Last week, we filed our summary judgment brief in Tin Cup, LLC v. United States Army Corps of Engineers. At its most particular, the case challenges the Corps’ assertion of Clean Water Act authority over permafrost on our client’s property outside of Fairbanks, Alaska. But on a larger plane, the case contests the Corps’ practice of expanding its wetlands jurisdiction through the issuance of so-called regional “supplements” to the congressionally mandated 1987 Wetlands Delineation Manual. In Tin Cup’s case, the Corps asserted authority over some 200 acres of permafrost on Tin Cup’s property. The Corps contends that permafrost qualifies as a wetland. But the Corps can make that assertion only by relying on the 2007 Alaska Supplement to the agency’s nationally applicable 1987 Manual. Had the Corps instead used the standards for wetland delineation contained within the 1987 Manual, the agency would have concluded that permafrost cannot be regulated under the Clean Water Act. Our brief argues that the Corps’ habit of expanding its jurisdiction through superseding “local rules” violates Congress’ direction that the agency operate under nationally applicable guidelines.