In the 1898 case of Hopkins v. United States, the Supreme Court ruled on a matter involving antitrust laws and their application to livestock traders in Kansas City. The defendants were members of a Live Stock Exchange who had agreed not to do business with any non-member commission firm or salesman at the stockyards. They were charged under the Sherman Antitrust Act for conspiring to restrain trade among several states by excluding non-members from participating in buying and selling livestock at these yards. However, they argued that their activities did not constitute interstate commerce as defined by law. The Supreme Court sided with the defendants, ruling that while livestock coming into Kansas City from various states was part of interstate commerce, once it arrived at its destination (the stockyards), it ceased being part of such commerce until sold and sent out again to other states. Therefore, agreements made regarding transactions within this local market did not fall under federal jurisdiction via antitrust laws because they didn't directly interfere with interstate trade.

In the dissenting opinion for Hopkins v. United States, it was argued that the Supreme Court had overstepped its jurisdiction by interpreting the Sherman Act to apply to a livestock exchange in Kansas City. The dissenting justices believed that this interpretation expanded federal power too broadly and infringed upon states' rights. They contended that while Congress has authority over interstate commerce, it does not have unlimited control over all activities related to commerce within individual states. In their view, a local livestock exchange did not constitute interstate trade simply because some of its members were from different states or because they occasionally dealt with out-of-state customers. Therefore, they concluded that applying federal antitrust laws in this case was inappropriate and beyond Congressional intent when passing the Sherman Act.