312 U.S. 126, 61 S.Ct. 524, 85 L.Ed. 624 ( 1941)
In UNITED STATES v. DARBY ( 312 U.S. 100), decided on the same day as the Opp case, the Supreme Court upheld the constitutionality of the Fair Labor Standards of Act of 1938 against the charge that it was not a valid regulation of interstate commerce, and that it violated the due process clause of the Fifth Amendment. In the Opp case, the appellant challenged the administrative scheme provided in the act. In essence, an Administrator was empowered to determine minimum wage rates in various industries, with the assistance of industry committees that would thoroughly investigate all the factors relevant to wage fixing. The Administrator was empowered to fix rates only within the limits of 30-40 cents per hour.
MR. JUSTICE STONE delivered the opinion of the court. . . .
There remains the question whether the Act is an unconstitutional delegation of the legislative power of Congress. Petitioner urges that the standards prescribed for fixing the authorized minimum wages between 30 and 40 cents per hour are too vague and indefinite to admit of any judicial determination whether they are within or without the standards prescribed by Congress.
It is not seriously urged that the policy and standards of the statute are subject to these criticisms independently of the provisions relating to classification. Section 8 defines, with precision, the policy of the Act to raise the minimum wage to the 40 cents per hour limit "as rapidly as economically feasible without substantially curtailing employment" in each industry, and the standards of the administrative action applicable to the Administrator are those made applicable to the committee which it is provided "shall recommend to the Administrator the highest minimum wage rates for the industry which it determines, having due regard to economic and competitive conditions, will not substantially curtail employment in the industry." But it is said that application of these standards in an industry is made contingent upon the determination whether the industry is to be classified and if so, whether it is to be subject to particular wage differentials, and that these determinations in turn depend upon factors so inadequately defined as to afford no standard of administrative action. . . .
The mandate of the. Constitution that all legislative powers granted "shall be vested" in Congress has never been thought to preclude Congress from resorting to -- the aid of administrative officers or boards as fact-finding agencies whose findings, made in conformity to previously adopted legislative. standards or definitions of congressional policy, have been made prerequisite to the operation of its statutory command. The adoption of the declared policy by Congress and its definition of the circumstances in which its command is to be effective, constitute the performance, in the constitutional sense, of the legislative function.