Abstract

The National Environmental Policy Act (NEPA) requires that an Environmental Impact Statement (EIS) be prepared whenever a proposed federal project will significantly harm the environment. The EIS must include an analysis of the environmental impacts of the project and an evaluation of alternatives. Federal regulations implementing NEPA mandate that an EIS include an evaluation of “reasonable” alternatives. Unfortunately, the regulations do not specify what constitutes a “reasonable” alternative. The courts have attempted for more than thirty years to come to grips with the problem of what makes an alternative “reasonable.” In this paper, I discuss court decisions that have significantly influenced our understanding. I offer my own interpretation, relying on a distinction between the “essential” purposes of a project and the non-essential, merely desirable, purposes. An alternative that satisfies the essential purposes of a project is reasonable and must be given an in-depth evaluation in the EIS. If adopted, my interpretation would enable NEPA to be more effective in promoting environmental values in the actions of federal agencies.