In the case of Union Pacific Railway Company v. Callaghan in 1895, the Supreme Court ruled on a dispute involving land rights and railroad construction. The plaintiff, Callaghan, claimed that he had acquired title to certain lands through preemption rights under federal law before they were granted to the Union Pacific Railway Company by Congress for railway construction purposes. The court held that even though Callaghan had filed his claim first, it was not approved until after Congress had granted these lands to Union Pacific. Therefore, at the time of Congressional grant to Union Pacific, there was no legal impediment preventing such grant because no final approval or certification of any preemptive right in favor of Callaghan existed then. Thusly, when his claim was finally allowed and certified later on - it could only relate back effectively from this date and did not affect or override prior existing grants like one given by Congress to Union Pacific earlier.

In the dissenting opinion for Union Pacific Railway Company v. Callaghan, Justice Brewer argued that the court majority had erred in its interpretation of law and precedent. He contended that a railroad company should be held liable for injuries sustained by an employee due to negligence on part of another employee, regardless of their relative positions within the company hierarchy. According to him, it was unjust to exempt companies from liability when lower-ranking employees were injured due to mistakes made by higher-ups; such a rule would essentially provide corporations with immunity while leaving workers vulnerable. Furthermore, he disagreed with the majority's assertion that this case was similar to previous ones involving independent contractors or fellow servants - instead asserting they were fundamentally different situations requiring distinct legal analyses and outcomes.