In the case of Rowland et al., Railroad Commissioners of the State of Arkansas, v. Boyle, Administrator of Boyle, and The St. Louis & San Francisco Railroad Company in 1916, the U.S Supreme Court was tasked with determining whether a state railroad commission had authority to regulate intrastate rates on interstate railroads that were already under federal regulation. This arose after an accident involving a train operated by The St. Louis & San Francisco Railroad Company resulted in death and subsequent lawsuit brought by Boyle's administrator against both the company and Arkansas' railroad commissioners (Rowland et al.). The court ruled that while states have power over local matters within their borders - including setting reasonable rates for intrastate commerce - they cannot interfere with or burden interstate commerce which is subject to federal control under Commerce Clause powers granted by Constitution; thus affirming supremacy clause principle where federal law takes precedence over conflicting state laws or regulations.

In the dissenting opinion for Rowland et al., Railroad Commissioners of the State of Arkansas, v. Boyle, Administrator of Boyle, and The St. Louis & San Francisco Railroad Company (1916), it was argued that the state's regulatory power over railroads should not be limited by federal courts unless there is a clear conflict with federal law or constitutional rights are violated. The dissenting justices believed that states have inherent police powers to regulate businesses within their borders for public safety and welfare purposes. They contended that this case did not involve any such conflicts or violations; therefore, they disagreed with the majority's decision to overturn an order from Arkansas' railroad commission requiring certain safety measures at railway crossings in Little Rock city limits where fatal accidents had occurred before.