cretion to refuse enforcement action. It first discussed this Court's opinions which have held that there is a general presumption that all agency decisions are reviewable under the APA, at least to assess whether the actions were "arbitrary, capricious, or an abuse of discretion." See Abbott Laboratories v. Gardner, 387 U. S. 136, 139–141 (1967); 5 U. S. C. § 706(2)(A). It noted that the APA, 5 U. S. C. § 701, only precludes judicial review of final agency action—including refusals to act, see 5 U. S. C. § 551(13)—when review is precluded by statute, or "committed to agency discretion by law." Citing this Court's opinions in Dunlop v. Bachowski, 421 U. S. 560 (1975), and Citizens to Preserve Overton Park v. Volpe, 401 U. S. 402 (1971), for the view that these exceptions should be narrowly construed, the court held that the "committed to agency discretion by law" exception of § 701(a)(2) should be invoked only where the substantive statute left the courts with "no law to apply." 231 U. S. App. D. C., at 146, 718 F. 2d, at 1184 (citing Citizens to Preserve Overton Park, supra, at 410). The court cited Dunlop as holding that this presumption "applies with no less force to review of ... agency decisions to refrain from enforcement action." 231 U. S. App. D. C., at 146, 718 F. 2d, at 1184.
The court found "law to apply" in the form of a FDA policy statement which indicated that the agency was "obligated" to investigate the unapproved use of an approved drug when such use became "widespread" or "endanger[ed] the public health." Id., at 148, 718 F. 2d, at 1186 (citing 37 Fed. Reg. 16504 (1972)). The court held that this policy statement constituted a "rule" and was considered binding by the FDA. Given the policy statement indicating that the FDA should take enforcement action in this area, and the strong presumption that all agency action is subject to judicial review, the court concluded that review of the agency's refusal was not foreclosed. It then proceeded to assess whether the agency's decision not to act was "arbitrary, capricious, or an abuse of discretion." Citing evidence that the FDA assumed
