In the case of El Paso and Southwestern Railroad Company v. Vizard in 1908, the U.S Supreme Court ruled on a dispute involving an injury to a railroad employee. The plaintiff, Vizard, was injured while working for the defendant company when he fell from a ladder that had been negligently placed by another employee. He sued under Texas law which allowed employees to recover damages for injuries caused by fellow servants' negligence if they were engaged in common employment. However, the defendant argued that federal law should apply instead as it did not hold employers liable for such accidents. The court held that state laws could be applied in cases involving interstate commerce only where they do not conflict with federal legislation or impede its operation; otherwise, federal law would preempt them. In this case though there was no specific federal statute covering employer liability for worker injuries at railroads involved in interstate commerce so Texas's common-law rule could apply. Therefore, despite operating across state lines (which normally brings activities within exclusive jurisdiction of Congress), since there was no conflicting Federal regulation or act regarding employer’s liability towards their workers’ safety during those times - State Law prevailed over Federal Law.

The dissenting opinion in the case of El Paso and Southwestern Railroad Company v. Vizard argued that the majority's decision was inconsistent with previous rulings regarding employer liability for employee injuries. The dissent contended that, under existing law, employers were not liable for injuries sustained by employees due to risks inherent in their work unless negligence could be proven on part of the employer. In this case, it was argued there was no evidence to suggest any negligence or failure on behalf of the railroad company to provide a safe working environment for its employees. Therefore, according to this view, Mr.Vizard assumed all risk associated with his job when he accepted employment and thus should not have been awarded damages following his injury at work.