Participants in a federal program to control the amount of wheat in the market agreed to produce a certain amount. In return, the federal government agreed to a higher price per bushel.
A farmer, producing more than his allotted share in order to provide for his personal use, will not buy that additional amount in the market. Multiplied that by a few million farmers and it would have a substantial affect on the interstate commerce that Congress was constitutionally regulating.
"Robert, not everything needs to be a federal case."
Not everything is.