United States v. Throckmorton was a United States Supreme Court case that dealt with the issue of whether a person could be convicted of a crime based on the testimony of an accomplice. The case involved a man named Throckmorton who was accused of counterfeiting coins. The prosecution's case relied solely on the testimony of an accomplice, and Throckmorton argued that this was insufficient to convict him. The Supreme Court ultimately ruled in favor of Throckmorton, holding that the testimony of an accomplice was not sufficient to convict a person of a crime. The Court reasoned that an accomplice's testimony was inherently unreliable and could not be used as the sole basis for a conviction. The Court also noted that the testimony of an accomplice should be corroborated by other evidence in order to be considered reliable. This case established an important precedent in criminal law, as it established that a person cannot be convicted of a crime based solely on the testimony of an accomplice. This precedent has been followed in subsequent cases and is still in effect today.

Justice Field delivered the dissenting opinion in United States v. Throckmorton, arguing that Congress did not have the power to pass a law criminalizing an act which was not considered illegal at common law. He argued that such a law would be unconstitutional because it would violate due process of law and deprive citizens of their liberty without due process of the laws established by Congress. Furthermore, he argued that if Congress had intended to make this type of conduct illegal, they should have done so explicitly rather than relying on implied powers granted by other statutes or constitutional provisions. Justice Field concluded his dissent with a warning about allowing too much discretion in interpreting congressional intent when determining whether certain acts are criminal or not; he warned against allowing courts to "make criminals" out of individuals who were otherwise innocent under existing laws.