The Protector was a Supreme Court case from 1870 that dealt with the issue of whether a patent for a steamboat was valid. The patent was granted to the inventor, John Fitch, in 1791. The case was brought by the heirs of Fitch, who argued that the patent was still valid and should be enforced. The Supreme Court ultimately ruled in favor of the heirs, finding that the patent was valid and enforceable. The Court reasoned that the patent was valid because it was issued before the Patent Act of 1793, which established the modern patent system. The Court also found that the patent was valid because it was issued before the invention of the steamboat, which was not invented until 1807. The Court also noted that the patent was issued before the invention of the steam engine, which was not invented until 1816. The Court's ruling was significant because it established that patents issued before the Patent Act of 1793 were still valid and enforceable. This ruling has been cited in numerous subsequent cases and has been used to support the validity of patents issued before the modern patent system was established.

In The Protector, the Supreme Court was asked to decide whether a vessel called "The Protector" could be seized by the United States government for failing to pay customs duties. Justice Field wrote a dissenting opinion in which he argued that the seizure of The Protector was unconstitutional because it violated Article I, Section 8 of the Constitution. He noted that Congress had no authority under this section to seize vessels for failure to pay taxes or duties and that any such power must come from an act of Congress specifically authorizing such seizures. Furthermore, he argued that even if there were an act allowing such seizures, it would still violate due process as guaranteed by Amendment V since no notice or hearing had been given prior to seizing The Protector. In conclusion, Justice Field asserted that while Congress may have broad powers over taxation and revenue collection they do not extend so far as permitting arbitrary seizures without proper legal proceedings being followed first.