In the case of Reading Company v. Koons, Administrator in 1925, the Supreme Court dealt with a dispute over whether an employer was liable for injuries sustained by an employee due to negligence on part of another employee. The plaintiff's decedent was killed while working as a brakeman for the defendant railroad company when he fell from a moving train car that had been negligently coupled by another worker. The lower court ruled in favor of the plaintiff and awarded damages based on Pennsylvania’s Employer Liability Act which held employers responsible for injuries caused by fellow employees' negligence during work hours. However, upon appeal to the Supreme Court, it was determined that this state law conflicted with federal legislation - specifically, Federal Employers’ Liability Act (FELA). FELA limited liability only to cases where injury resulted from employer's or superior officer's negligence but not co-workers'. Therefore, under FELA provisions applicable here since interstate commerce was involved (the train being operated across state lines), no liability could be assigned to Reading Company because there wasn't any evidence showing its direct fault or neglect contributing towards accident. The Supreme Court thus reversed previous judgment stating that federal law superseded conflicting state laws in matters concerning interstate commerce.

In the dissenting opinion for Reading Company v. Koons, it was argued that the majority's decision to uphold a Pennsylvania statute allowing double recovery in wrongful death cases involving railroads violated due process and equal protection clauses of the Fourteenth Amendment. The dissent contended that this law unfairly singled out railroad companies for harsher treatment than other corporations or individuals who might be defendants in similar lawsuits. It also suggested that such punitive measures should not be allowed without clear legislative intent, which was absent here as per their interpretation of Pennsylvania law. Furthermore, they disagreed with the majority's view on how federal courts should handle state laws potentially conflicting with constitutional rights; instead advocating for a more active role in scrutinizing these statutes rather than deferring to state interpretations.