John C. Hays brought a case against the Pacific Mail Steam-Ship Company to the Supreme Court of California in 1854. He argued that he had been wrongfully discharged from his position as an engineer on one of their ships, and sought compensation for lost wages and damages. The company defended itself by claiming that they had just cause to terminate his employment due to misconduct on board the vessel, including intoxication while at sea. The court ultimately sided with Hays, ruling that there was insufficient evidence presented by the company to prove any misconduct or wrongdoing on behalf of Hays during his time working for them; thus, they were liable for all losses incurred as a result of wrongful termination. This decision set an important precedent regarding employee rights in cases involving unjustified firings or terminations without proper justification being provided by employers.

Justice McLean wrote a dissenting opinion in the case of John C. Hays v. The Pacific Mail Steam-Ship Company, arguing that the majority's decision was incorrect and should be reversed. He argued that under maritime law, when goods are shipped on board a vessel for transportation from one port to another, they become part of the ship and its cargo; thus, any damage or loss is borne by both parties equally unless there is proof of negligence or fault on either side. In this case, he noted that no evidence had been presented to show any negligence or fault on either party’s part; therefore it was unfair for Hays to bear all responsibility for the lost goods as determined by the majority ruling. Justice McLean concluded his dissent with an argument against allowing carriers such broad discretion over their customers' property without providing adequate protection against potential losses due to unforeseen circumstances beyond their control.