In 2013, the groups WildEarth Guardians and the New Mexico Wilderness Alliance sued the Justice Department over the McKittrick Rule, saying that by following the rule, the Department was being derelict in its duties to enforce federal law. The groups, whose suit was driven in large part by the plight of the Mexican wolf, also claimed that the rule was an improper overreach by the Justice Department. They claimed that Justice was claiming broad authority in interpreting the language in the Endangered Species Act, a power traditionally reserved for the courts.In its finding on June 21, the U.S District Court for the District of Arizona ruled that the Justice Department’s adherence to the McKittrick Rule was an illegal end-run around the will of Congress in writing the Endangered Species Act:

Source: Court Scraps Endangered Species Killing Loophole | KCET