Justice William Rufus Day (majority): “In interpreting the Constitution it must never be forgotten that the nation is made up of states to which are entrusted the powers of local governments. And to them and to the people the powers not expressly delegated to the national government are reserved.”

Justice Oliver Wendell Holmes (dissenting): “The Act does not meddle with anything belonging to the States. They may regulate their internal affairs and their domestic commerce as they like. But when they seek to send their products across the State line they are no longer within their rights. If there were no Constitution and no Congress their power to cross the line would depend upon their neighbors. Under the Constitution such commerce belongs not to the States but to Congress to regulate.”