490 U.S. 332 (1989), Supreme Court of the United States
Robertson v. Methow Valley Citizens Council is a cornerstone Supreme Court decision clarifying the scope of the National Environmental Policy Act (NEPA).
Under NEPA, must an agency's EIS include (1) a detailed, fully developed and enforceable mitigation plan for identified harms and (2) a "worst-case" analysis when information is incomplete or uncertain; and, in light of these standards, was the Forest Service's EIS for the proposed ski resort adequate?
NEPA imposes procedural—not substantive—obligations: an agency must take a "hard look" at environmental consequences and disclose them to the public before acting. An EIS must include a reasonably thorough discussion of significant environmental impacts and "possible mitigation measures," but NEPA does not require the adoption of any particular mitigation, nor a fully developed, enforceable mitigation plan at the EIS stage. CEQ's regulations interpreting NEPA are entitled to substantial deference. Under CEQ's 1986 revision of 40 C.F.R. § 1502.22, agencies need not prepare a "worst-case" analysis; instead, they must disclose when information is incomplete or unavailable, explain its relevance, summarize credible scientific evidence, and evaluate reasonably foreseeable significant adverse effects and their likelihood.
No. NEPA does not require a fully developed and enforceable mitigation plan in the EIS, and it does not require a "worst-case" analysis. The Forest Service's EIS, which discussed potential mitigation measures and disclosed uncertainties, satisfied NEPA's procedural requirements. The Ninth Circuit's decision was reversed.
Robertson is a leading case on NEPA's scope. It cements that NEPA is a disclosure statute: agencies must analyze and disclose impacts and mitigation, but NEPA does not require them to select the most environmentally protective alternative or to finalize a mitigation plan in the EIS. The decision also establishes substantial judicial deference to CEQ's NEPA regulations and confirms that a "worst-case" analysis is not required. For students and practitioners, Robertson defines what makes a mitigation discussion adequate, highlights how agencies should handle incomplete information, and frames the "hard look" review that courts apply to EIS adequacy challenges.