In the 1966 case of Waldron v. Moore-McCormack Lines, Inc., the U.S Supreme Court was tasked with determining whether a seaman could recover damages for injuries sustained while off-duty and ashore under the Jones Act or general maritime law. The plaintiff, Waldron, had been injured during his shore leave in Buenos Aires when he fell into an open hatch on a docked ship owned by Moore-McCormack Lines. He argued that his employer should be held liable as they failed to provide him safe passage back to their vessel after granting him permission to go ashore. However, both lower courts ruled against Waldron's claims. The Supreme Court reversed these decisions and sided with Waldron stating that seamen are wards of admiralty law and have special protections due to their exposure to perils of sea life which extends even during periods ashore if connected with service at sea. Therefore, it concluded that employers owe them duty-of-care not only aboard but also while going between ship and shore during sanctioned leaves.

In the dissenting opinion for Waldron v. Moore-McCormack Lines, Inc., Justice Harlan disagreed with the majority's decision to apply a negligence standard in this case involving an injured seaman under the Jones Act. He argued that Congress intended for a higher level of protection and compensation for seamen due to their exposure to unique perils at sea, which is why they adopted "unseaworthiness" as a legal concept distinct from negligence. According to him, by conflating these two concepts, the majority undermined this intention and effectively reduced protections afforded to seamen under maritime law. Furthermore, he contended that there was sufficient evidence presented during trial demonstrating unseaworthiness of the ship independent of any negligent actions on part of its crew or officers; hence it was incorrect not only legally but also factually for lower courts and now Supreme Court itself dismissing plaintiff’s claim based solely on absence of proven negligence.