Clarke v. United States was a Supreme Court case that addressed the issue of whether a defendant could be convicted of a crime if the indictment was not found by a grand jury. The case involved a man named Clarke who was charged with a crime in the District of Columbia. The indictment was not found by a grand jury, but instead was found by a single judge. Clarke argued that the indictment was invalid because it was not found by a grand jury, as required by the Fifth Amendment. The Supreme Court held that the indictment was valid and that a defendant could be convicted of a crime even if the indictment was not found by a grand jury. The Court reasoned that the Fifth Amendment only required that a grand jury be used in certain cases, and that the District of Columbia was not one of those cases. The Court also noted that the District of Columbia had its own laws and procedures, and that the Fifth Amendment did not apply to the District of Columbia. The Court's decision in Clarke v. United States established that a defendant could be convicted of a crime even if the indictment was not found by a grand jury. This decision has been cited in numerous cases since then, and has been used to support the idea that a defendant can be convicted of a crime even if the indictment was not found by a grand jury.

In Clarke v. United States, the Supreme Court was asked to decide whether a defendant convicted of manslaughter could be sentenced to hard labor in addition to being fined and imprisoned. The majority opinion held that Congress had the power under Article I, Section 8 of the Constitution to impose such a sentence. Justice Field dissented from this decision on two grounds: firstly, he argued that Congress did not have authority over criminal law matters as they were reserved for state governments; secondly, he argued that even if it did have such authority, imposing hard labor would constitute cruel and unusual punishment which is prohibited by both common law and the Eighth Amendment. He concluded by stating his belief that "the judgment should be reversed".