For detail:
- Oyez: United States v. Darby.
- Wikipedia: United States v. Darby.
The facts of the case from Wikipedia:
The issue was whether Congress had overstepped its constitutional authority in creating the Fair Labor Standards Act. An American lumber company in Georgia that did not meet these standards was charged with violating the law, but had won an appeal, where the appellate judge found that the federal government is barred by the 10th Amendment from interfering in matters that are strictly local, that is, within state boundaries. The Act also required the keeping of records to verify compliance; the appellee argued that this violated his 5th Amendment right protecting him from self-incrimination.
The Court reversed the appellate court decision. It affirmed the constitutional power of Congress to regulate interstate commerce, which power "can neither be enlarged nor diminished by the exercise or non-exercise of state power." FindLaw. The Court held that the purpose of the Act was to prevent states from using substandard labor practices to their own economic advantage through interstate commerce. In the Dagenhart case, the Court had made the distinction between manufacturing and interstate commerce, so that a business could argue it was engaging in the former, but had not intended the latter. Twenty-two years later, the Court found that earlier argument facile, explaining that Congress was well aware that businesses produce their goods without thought to where they will go; product is pulled and shipped to meet the orders of the day. The Court also found that the requirement of record keeping was entirely appropriate as a matter of enforcing the Act.