In the 1946 case of Jesionowski v. Boston & Maine Railroad, the U.S. Supreme Court ruled in favor of Mrs. Jesionowski, who was suing on behalf of her deceased husband's estate after he died from injuries sustained while working for Boston & Maine Railroad. The court held that under the Federal Employers' Liability Act (FELA), a railroad worker injured on duty could sue his employer if negligence contributed to his injury "in whole or in part." This ruling overturned an earlier decision by a lower court which had dismissed Mrs. Jesionowski's lawsuit because she failed to prove that her husband’s death resulted solely from negligence by the railroad company and not due to any contributory negligence on Mr.Jesionowski’s part.

In the dissenting opinion for Jesionowski v. Boston & Maine Railroad, Justice Frankfurter disagreed with the majority's interpretation of Federal Employers' Liability Act (FELA). He argued that the majority had expanded FELA beyond its original intent by allowing a plaintiff to bring a case without providing evidence of negligence on part of the employer. According to him, this decision would lead to an increase in litigation and potential abuse as it essentially shifted from requiring proof of negligence to presuming it unless proven otherwise by employers. The justice believed that such an approach was not only unfair but also inconsistent with previous court rulings interpreting FELA which required plaintiffs to provide substantial evidence proving their employer’s negligence caused their injury.