See Ass’n of Nat’l Advertisers, 627 F.2d at 1168 (“Rulemaking involves the kind of issues ‘where a month of experience will be worth a year of hearings.’ ” (quoting Am. Airlines, Inc. v. Civil Aeronautics Bd., 359 F.2d 624, 633 (D.C.Cir.1966))). Similarly, we cannot forget that the legislature, like Congress, “is not confined to that method of executing its policy which involves the least possible delegation of discretion to administrative officers.” Fates v. United States, 321 U.S. 414, 425-26, 64 S.Ct. 660, 668, 88 L.Ed. 884, 849 (1944). On the contrary, the discretion can be quite significant so long as an “intelligible principle” exists to guide its exercise. See Whitman v. Am. Trucking Ass’ns, Inc., 531 U.S. 457, 474, 476, 121 S.Ct. 903, 913, 914, 149 L.Ed.2d 1, 17, 18 (2001) (<HOLDING>). Finally, the Iowa Constitution also contains
holding that epa rule relating to repair of cars not in compliance with clean air act was interpretative not legislative rule and thus not subject to apa notice and comment procedures holding the epa could regulate air pollutants under the clean air act solely on the basis of the pollutants risk to human health holding for a citizen suit brought under a substantially identical provision of the clean air act that whether plaintiffs have established a nondiscretionary duty to act by the epa is a merits question under rule 12b6 rather than a subjectmatter jurisdiction question under rule 12b1 holding that case law from other circuits squarely precluded jurisdiction over preenforcement ruling under the clean air act holding that defendant could not be sanctioned and found to have violated the clean air act when it complied with regu lations as codified despite having knowledge that the epa requested amendment of the regulations to prohibit defendants conduct