In 1946, Congress enacted the Administrative Procedure Act, which as we have noted elsewhere was not only "a new, basic and comprehensive regulation of procedures in many agencies," Wong Yang Sung v. McGrath, 339 U.S. 33 (1950), but was also a legislative enactment which settled "long-continued and hard-fought contentions, and enacts a formula upon which opposing social and political forces have come to rest." Id., at 40. Section 4 of the Act, 5 U. S. C. ? 553 (1976 ed.), dealing with rulemaking, requires in subsection (b) that
