Over the past three years, the courts have had many opportunities to interpret NEPA. The Act has been involved in 149 separate litigations, some of which have produced several opinions. Yet, Chapters IV, V, and VI abundantly confirm that the bulk of these interpretations focuses on the one short action-forcing provision set out in §102(2) (C). As important as that section is, its role is nevertheless an essentially subservient one. An archive of disregarded assessments that bring about no real improvement in federal decisionmaking might satisfy §102(2) (C), but would fail NEPA as a whole. Aware of this possibility, the courts have endorsed a wider judicial role in ensuring that final agency decisionmaking actually reflects NEPA's substantive policy.

In addition to interpreting the information and disclosure requirements of §102(2) (C), the courts have spelled out how that information must be "considered" by the agency in making its final decision. The use to which environmental information is put in decisionmaking is fully reviewable, and the impact statement plays an important role as part of the reviewable record of consideration. Furthermore, several courts have held that courts may review agency decisions to determine if they are in accord with NEPA's substantive policy.