ern R. Co. v. Seaboard Allied Milling Corp, 442 U. S. 444 (1979), and Dunlop v. Bachowski, 421 U. S., at 567. But one could read the language "committed to agency discretion by law" in § (a)(2) to require a similar inquiry. In addition, commentators have pointed out that construction of § (a)(2) is further complicated by the tension between a literal reading of § (a)(2), which exempts from judicial review those decisions committed to agency "discretion," and the primary scope of review prescribed by § 706(2)(A)—whether the agency's action was "arbitrary, capricious, or an abuse of discretion." How is it, they ask, that an action committed to agency discretion can be unreviewable and yet courts still can review agency actions for abuse of that discretion? See 5 K. Davis, Administrative Law § 28:6 (1984) (hereafter Davis); Berger, Administrative Arbitrariness and Judicial Review, 65 Colum. L. Rev. 55, 58 (1965). The APA's legislative history provides little help on this score. Mindful, however, of the common-sense principle of statutory construction that sections of a statute generally should be read "to give effect, if possible, to every clause ...," see United States v. Menasche, 348 U. S. 528, 538–539 (1955), we think there is a proper construction of § (a)(2) which satisfies each of these concerns.
This Court first discussed § (a)(2) in Citizens to Preserve Overton Park v. Volpe, 401 U. S. 402 (1971). That case dealt with the Secretary of Transportation's approval of the building of an interstate highway through a park in Memphis, Tennessee. The relevant federal statute provided that the Secretary "shall not approve" any program or project using public parkland unless the Secretary first determined that no feasible alternatives were available. Id., at 411. Interested citizens challenged the Secretary's approval under the APA, arguing that he had not satisfied the substantive statute's requirements. This Court first addressed the "threshold question" of whether the agency's action was at all reviewable. After setting out the language of § 701(a), the Court stated:
