Inc. Baldwin v. G. A. F. Seelig

Justice Cardozo gave the Court's opinion, the only opinion on record for the case. He began by clarifying the issue, stating that New York was only trying to limit the sale of milk purchased from another state, not the purchase itself. But even so, Cardozo noted, the act violated the Constitution and presented a barrier to interstate traffic every bit as effective as the tariff by which independent nations often restrict trade. Article I, Section 8, Clause 3, the "commerce clause," gives power over interstate commerce to Congress, not the states. Therefore, "it is the established doctrine of this court that a state may not, in any form or under any guise, directly burden the prosecution of interstate business."

With regard to the argument that New York milk producers should be kept in business in order to maintain state control over the milk industry for the sake of its citizens' health, Cardozo saw this only as a smokescreen for protection of local industry. Furthermore, if one state is able to make an exception to the commerce clause, he suggested, this paves the way for each state to make its own laws regarding trade. In other words to behave as though it were a nation rather than a state that is subject to the federal government. To allow this, Cardozo remarked ominously, "would be to invite a speedy end of our national solidarity." As for any possible argument that underpaid farmers in New York would seek to relax sanitary controls in order to cut costs, Cardozo again dismissed the idea. Such actions on the part of a farmer, he said, would have to be dealt with by more direct methods designed specifically to prevent the sale of milk that does not meet health standards. Presumably, such laws were already in place.