In the case of McAllister v. Magnolia Petroleum Co., 1957, the U.S Supreme Court ruled in favor of Magnolia Petroleum Company (now ExxonMobil). The dispute arose when a seaman employed by Magnolia was injured on one of their barges and sued for damages under the Jones Act, which provides compensation to sailors for injuries suffered during employment. However, it was found that at the time of his injury he was not acting within his duties as a sailor but rather performing tasks related to loading cargo onto another vessel owned by an independent contractor. Therefore, he did not qualify as a "seaman" under the Jones Act at that specific moment and could not claim its benefits. This ruling established precedent regarding who qualifies as a "seaman" under maritime law and highlighted how job function can affect this status.

In the dissenting opinion for McAllister v. Magnolia Petroleum Co., Justice Brennan, joined by Chief Justice Warren and Justice Black, argued that the majority's decision to uphold a state law prohibiting non-residents from serving as executors of estates was inconsistent with previous Supreme Court rulings on interstate commerce. They contended that this law unfairly discriminated against out-of-state residents in violation of the Privileges and Immunities Clause of Article IV and the Commerce Clause of the U.S Constitution. The dissenters believed that such discrimination could only be justified if it served a substantial state interest - which they did not believe existed in this case. Furthermore, they disagreed with the majority's assertion that there were practical difficulties associated with an out-of-state executor managing an estate; pointing out advancements in communication technology made management from afar feasible.