In Mullan v. United States (1908), the U.S Supreme Court dealt with a dispute over land ownership in Idaho. The plaintiff, John Mullan, claimed that he had acquired title to certain lands through preemption rights and mining claims before they were included within an Indian reservation by executive order. However, the government argued that these lands were part of Coeur d'Alene Indian Reservation and thus not subject to preemption or mining claim laws at the time when Mullan purportedly made his claims. The court sided with the government's argument stating that even though there was no formal treaty establishing this reservation until later, evidence showed it was treated as such from its inception by both local settlers and federal officials. Therefore, it held that these lands were indeed part of an established Indian reservation at all relevant times which meant they could not be preempted or claimed for mining purposes under existing law. This case reaffirmed principles regarding tribal sovereignty and federal trust responsibility towards Native American tribes while also clarifying how courts should interpret historical records concerning establishment of reservations.

In the dissenting opinion for Mullan v. United States, Justice Harlan argued that the majority's decision failed to properly interpret and apply existing mining laws. He believed that these laws were designed to encourage mineral exploration and development by granting exclusive rights to those who first discovered valuable deposits on public lands. In this case, he felt that Mullan had met all legal requirements for establishing his claim over a particular piece of land before anyone else did so. Therefore, according to Harlan, it was unjust for the government later to deny him ownership based on technicalities about how exactly he marked his claim boundaries - especially since there was no evidence of any intent or attempt at fraud or deception in his actions.