Upton v. Mason was a United States Supreme Court case that dealt with the issue of whether a state court had the authority to issue a writ of mandamus to a federal court. The case arose when the plaintiff, Upton, sought to have the defendant, Mason, removed from his position as a federal court judge. Upton argued that Mason had acted in a manner that was prejudicial to the interests of the United States and that he should be removed from office. The Supreme Court held that the state court did not have the authority to issue a writ of mandamus to a federal court. The Court reasoned that the writ of mandamus was a remedy that was available only to the federal courts and that the state court did not have the authority to issue such a writ. The Court also held that the state court did not have the authority to review the actions of a federal court judge. The Court concluded that the state court lacked the authority to issue a writ of mandamus to a federal court and that the plaintiff's claim must be dismissed.

Justice Harlan delivered the dissenting opinion in Upton v. Mason, a case concerning the validity of an assignment of a patent for an invention. He argued that while it was true that patents were personal property and could be assigned, this did not mean they could be used to create monopolies or restrain trade. The majority had held that such assignments were valid under certain circumstances; however, Justice Harlan disagreed with this conclusion because he believed it would lead to unjustified restrictions on competition and innovation in the marketplace. He noted that Congress had never intended for patents to be used as instruments of monopoly power when they passed legislation creating them and thus any attempt by courts to expand their scope beyond what Congress originally envisioned should not be allowed. Furthermore, Justice Harlan argued that allowing these types of assignments would have negative economic consequences since it would reduce incentives for inventors who might otherwise choose not to pursue their ideas due to fear of having them taken away from them through unfair means like patent assignments. Ultimately, his dissent sought to protect both inventors’ rights as well as free market principles by advocating against expanding the scope of patent law beyond its original intent set forth by Congress