In the United States v. Shea case of 1893, the Supreme Court ruled on a dispute involving land rights in California. The defendant, Shea, claimed ownership over certain lands under an old Mexican grant which had been confirmed and patented by U.S authorities. However, it was later discovered that part of this land overlapped with public lands reserved for railroad purposes under an act of Congress from 1866. The government sued to annul the patent so far as it included these overlapping lands. The court held that while there were errors in issuing patents including such reserved lands, they did not warrant complete nullification but rather required correction or adjustment through appropriate legal procedures. It further clarified that Congressional acts granting right-of-way for railroads do not automatically divest public lands off all valuable uses other than railroad purposes; hence they remain subject to disposal under general laws unless explicitly withdrawn. Therefore, although Shea's patent mistakenly included some reserved areas due to inaccurate surveys at the time of confirmation and issuance - he could still maintain his claim over non-reserved portions within his granted boundaries.

The dissenting opinion in the United States v. Shea case argued that the defendant, a customs inspector accused of receiving illegal fees, should not have been convicted because he was acting under orders from his superiors and believed he was following lawful instructions. The justice contended that Shea had no reason to believe his actions were unlawful as they were consistent with established practices at the time and approved by higher authorities within the Customs Service. Therefore, it would be unjust to hold him criminally responsible for obeying what he reasonably thought were legitimate commands from his supervisors. This viewpoint emphasized on individual's responsibility being mitigated when their actions are carried out under direct orders or influence of authority figures who are expected to know better about legality or illegality of such directives.