Treehuggers, a conservationist organization with standing to bring action for injunction against the U.S. Forest Service, claims among other things, that the U.S. Forest Service violated the provisions of NEPA by opening up new lands to timber operations without preparing an EA or EIS evaluation. Assuming NEPA's standards apply to the U.S. Forest Service in this case, what would Treehuggers have to prove in order for a court to set aside the Agency's decision?