Agriculture your username May 6, 2021 The U.S. Army Corps of Engineers asked the Ninth Circuit on Tuesday to vacate decisions in a lawsuit regarding the 2017 version of Nationwide Permit 12 (NWP 12) purporting that the case, and its appeals, are moot now because the Keystone XL pipeline was cancelled. NWP-12 is a general permit for utility lines that is re-issued after a few years. It allows for pipelines to be built over areas of water. Approval through the NWP 12 permit is simpler than approving a new project where the pipeline would cross water through the normal methods, which environmental groups alleged breaches federal environmental laws.