It frequently happens that the federal government and a state government attempt to regulate the same commercial activity — or what may appear to be the same commercial activity. If the laws or regulations are in agreement, there is no problem. But suppose they are not in agreement. Here, the problems arise. The teaching of the numerous judicial decisions appears to be that even if the state requirement in issue is different from the federal, if it is not in direct conflict with the federal, and does not interfere with the policy or administration of the federal, the two may co-exist and both be enforced. But if the state requirement is in direct conflict with the federal and interferes with the policy or administration of the federal, the federal law or regulation will prevail over the state, and the state law or regulation will be stricken down. In this situation, the federal government with its paramount constitutional power to regulate interstate commerce, is said to have occupied or preempted the particular field of government control and thereby to have excluded regulation by the state. This doctrine, articulated in the foregoing or comparable language, has been applied in numerous cases involving the regulation of commerce in food products. There are cases, for example, involving federal versus state food standards, and these are of particular interest.
1Presented at 15th Annual Meeting of the Dairy Products Improvement Institute, Inc., Hotel Governor Clinton, New York City, February 15, 1962.