Inland Empire Public Lands Council v. United States Forest Service 88 F.3d 754 (9th Cir. 1996) The US Forest Service proposed some timber sales in a National Forest in Montana. Environmental groups (led by IEPLC) sued for an injunction. IEPLC argued that the sales would have a negative impact on a number of animal species in the forest. IEPLC argued that this was a violation of the National Forest Management Act (NFMA), and the National Environmental Policy Act (NEPA). Even though the Forest Service had performed an assessment, IEPLC argued that it was insufficient because the scientific methods used were flawed. The Trial Court found for the Forest Service. IEPLC appealed. The Trial Court found that there was simply a disagreement over the choice of scientific methodologies. The Court found that based on Chevron U.S.A. Inc. v. Natural Resources Defense Council (467 U.S. 837 (1984)) they should defer to Agency judgment. The Appellate Court affirmed. The Appellate Court noted that Forest Service regulations (36 C.F.R. §219.19) required the Forest Service to perform a minimum level of population viability analysis. The Court found that the science the Forest Service used might be arguable, but it was not arbitrary and capricious, and so the courts should defer to the Forest Service's judgment. This case is another example of how it is very difficult to overturn an Agency decision by arguing that they are using a bad scientific method as opposed to a good one. As long as the Agency has a scientific basis for their decision, the courts will almost always defer to their judgment. For another example, see Sierra Club v. Marita (46 F.3d 606 (1995)). But, the Agency must have at least some factual basis for their decision, they can't just make a decision based on nothing at all. See Ecology Center, Inc. v. Austin (430 F.3d 1057 (2005)).