Tilghman v. Procto was a United States Supreme Court case that addressed the issue of whether a state court could enjoin a federal court from hearing a case. The case involved a dispute between two parties over a contract for the sale of a steamboat. The plaintiff, Tilghman, had filed a suit in a federal court in Pennsylvania to recover damages for the breach of the contract. The defendant, Procto, then filed a suit in a state court in Maryland seeking an injunction to prevent the federal court from hearing the case. The Supreme Court held that the state court did not have the authority to enjoin the federal court from hearing the case. The Court reasoned that the state court lacked jurisdiction over the federal court, and that the federal court had exclusive jurisdiction over the case. The Court also noted that the state court's injunction would interfere with the federal court's ability to exercise its jurisdiction. The Court's decision in Tilghman v. Procto established that state courts cannot enjoin federal courts from hearing cases. This decision has been cited in numerous subsequent cases, and it remains an important precedent in the area of federal court jurisdiction.

In Tilghman v. Proctor, the United States Supreme Court was asked to decide whether a patent issued by the U.S. Patent Office for an invention of a machine used in manufacturing paper could be infringed upon without violating federal law. The majority opinion held that it could not, as Congress had not provided any protection against infringement on such patents at the time of issuance and thus no violation occurred when one party copied another's patented invention without permission or payment of royalties. However, Justice Field dissented from this decision and argued that although Congress had not specifically protected these types of inventions from infringement at the time they were issued, it did provide general protections against unauthorized use or copying under existing copyright laws which should have been applied in this case to protect Tilghman’s rights as inventor and patent holder over his machine design. He further argued that since there is no evidence suggesting otherwise, Congress must have intended for its copyright laws to apply broadly enough so as to include all forms of intellectual property regardless if specific legislation existed protecting them at their respective times of issue or creation; therefore he concluded that Proctor’s actions constituted an unlawful infringement on Tilghman’s patent rights and should be subject to legal action accordingly