In Levinson v. Spector Motor Service, the U.S. Supreme Court ruled on a case involving an interstate motor carrier and its employee who was injured while working in Connecticut. The issue at hand was whether or not federal law preempted state workers' compensation laws when it came to injuries sustained by employees engaged in interstate commerce activities. The court held that the Federal Employers' Liability Act did not apply because it only covered railroad workers, and therefore did not preclude application of state worker's compensation laws for non-railroad employees involved in interstate commerce. Thus, the court affirmed that state worker's compensation laws could be applied to such cases.

In the dissenting opinion for Levinson v. Spector Motor Service, Justice Frankfurter argued that the court's decision to allow an employee to sue his employer under a federal statute was incorrect. He believed that this interpretation of the law expanded its scope beyond what Congress had intended when it passed the legislation. According to him, Congress meant for employees injured while working in interstate commerce to be able to seek compensation from their employers only if they were not covered by state workers' compensation laws. In other words, he thought that federal law should serve as a safety net rather than as an alternative avenue for legal recourse. Furthermore, he expressed concern about potential inconsistencies and conflicts between state and federal laws regarding worker injuries due to this ruling.