In Citizens to Preserve Overton Park v. Volpe, 401 U.S. 402, 415, 91 S.Ct. 814, 823, 28 L.Ed.2d 136, 153 (1971), the Secretary of Transportation rendered a decision following a statutorily-required public hearing designed to afford community imput on the matters to be determined a hearing "nonevidentiary, quasi-legislative in nature," necessitating no formal findings of fact. On review in a district court, the parties introduced opposing affidavits addressing the validity of the decision, and the affidavits served as the foundation for judicial scrutiny. The Supreme Court held that de novo consideration was not authorized, and that "(t)hese affidavits were merely 'post hoc rationalizations' . . . which have traditionally been found to be an inadequate basis for review . . .. (T)hey clearly do not constitute the 'whole record' compiled by the agency: the basis for review required by 706 of the (Administrative Procedure Act)."Review is rather "to be based," the Court said, "on the full administrative record that was before the Secretary at the time he made his decision." In Citizens to Preserve Overton Park, Inc. v. Volpe, 401 U.S. 402 (1971), the Court explained the distinction between 5 U.S. C. 701(a)(1) and (a)(2). Subsection (a)(1) is concerned with whether Congress expressed an intent to prohibit judicial review; subsection (a)(2) applies "in those rare instances where `statutes are drawn in such broad terms that in a given case there is no law to apply.' " 401 U.S., at 410 (citing S. Rep. No. 752, 79th Cong., 1st Sess., 26 (1945)). The Court further explained what it means for an action to be "committed to agency discretion by law" in Heckler v. Chaney, 470 U.S. 821 (1985). The Supreme Court made clear that where the administrative record does not disclose the reasons for particular administrative action, it may be necessary for the District Court to require some explanation in order to determine if the Secretary acted within the scope of his authority and if the Secretarys action was justifiable under the applicable standard. The Court stated that the preclusion of judicial review for action committed to agency discretion by law is 'a very narrow exception.' Id. at 410. Judicial review should be disallowed only in those 'rare instances' where the 'statutes are drawn in such broad terms that in a given case there is no law to apply.' Id. at 410, quoting from S.Rep. No. 752, 79th Cong., 1st Sess. 26 (1945).