Darby produced lumber with labor that violated the Fair Labor Standards Act, and accordingly, it was indicted and fined.
Congress has the power to regulate intrastate activities when those intrastate activities are related to interstate commerce.
Darby acquires raw timber and turns it into finished lumber, with the intention of selling and shipping it outside the state. Darby’s lumber was produced with labor that violated the Fair Labor Standards Act, and accordingly, it was indicted and fined.
Does Congress have the power to prohibit the interstate shipment of lumber manufactured by employees whose wages are less than a prescribed minimum, or whose weekly hours of labor at that wage are greater than a prescribed maximum?
And, does Congress have the power to prohibit the employment of workmen in the production of goods for interstate commerce at other than prescribed wages and hours?
Yes, and yes. Congress has the power to regulate these issues.
Manufacturing is not interstate commerce, but the shipment of manufactured goods among states is interstate commerce.
The power to regulate commerce is completely under Congressional control. Congress can conceptualize public policy concerning interstate commerce, including imposing restrictions and excluding articles that could be injurious to the public health, morals or welfare, even if the state has not sought to regulate in that space.
Hammer v. Dagenhart, which held that Congress could not regulate in this space, has not been followed and is overturned.
Congress can choose the means reasonably adapted to the attainment of the permitted end–regulating interstate commerce–even if the means involve control of intrastate activities.