In Kernan, Administrator v. American Dredging Co., the Supreme Court ruled on a case involving maritime law and jurisdictional issues. The plaintiff was injured while working aboard a dredge in Pennsylvania waters and sued his employer under the Jones Act, which allows seamen to sue their employers for personal injuries caused by negligence. However, the defendant argued that since it operated exclusively within Pennsylvania's territorial waters, it should be subject only to state laws rather than federal maritime laws such as the Jones Act. The court held that even though operations were confined to one state’s waterways, they still fell under admiralty jurisdiction because of their connection with interstate commerce and navigation. Therefore, federal maritime law applied including provisions of the Jones Act allowing for negligence claims against employers.

The dissenting opinion in the case of Kernan v. American Dredging Co., argued that the majority's decision to allow a state court to exercise jurisdiction over an out-of-state defendant based on their contractual relationship with an in-state plaintiff was inconsistent with due process principles. The dissent contended that this ruling expanded the reach of personal jurisdiction too far, potentially subjecting defendants to litigation in any state where they have business contacts, regardless of whether those contacts are related to the lawsuit at hand. This could lead to unfairness and unpredictability for businesses operating across state lines. Furthermore, it was argued that such broad interpretation undermines federalism by allowing states' laws and courts undue influence over non-residents who may not have meaningful connections or protections within those jurisdictions.