Filor v. United States was a Supreme Court case that dealt with the issue of whether a defendant could be convicted of a crime if the indictment was not found by a grand jury. The case was brought by a man named Filor, who was convicted of a crime without a grand jury indictment. Filor argued that the conviction was unconstitutional because the Fifth Amendment of the United States Constitution states that no person shall be held to answer for a capital or otherwise infamous crime unless on a presentment or indictment of a grand jury. The Supreme Court ruled in favor of Filor, finding that the Fifth Amendment requires a grand jury indictment for a criminal conviction. The Court held that the Fifth Amendment was intended to protect the accused from arbitrary and oppressive prosecutions, and that a grand jury indictment was necessary to ensure that the accused was not subject to such prosecutions. The Court also noted that the grand jury was an important part of the criminal justice system, and that its role was to protect the accused from unfounded charges. The Court's decision in Filor v. United States established the precedent that a grand jury indictment is necessary for a criminal conviction. This precedent has been followed in subsequent cases, and is still in effect today.

In Filor v. United States, the Supreme Court was asked to decide whether a defendant could be convicted of two separate offenses for one act. The majority opinion held that the defendant could not be convicted twice for one act, but Justice Field dissented from this ruling. He argued that Congress had intended to punish certain acts more severely than others and thus it should have been permissible in this case to convict the defendant of both offenses as they were distinct crimes with different punishments prescribed by law. Furthermore, he noted that there was no double jeopardy clause in effect at the time and so allowing multiple convictions would not violate any constitutional rights or protections afforded to defendants under existing laws. In conclusion, Justice Field believed that Congress had made its intent clear when enacting these statutes and therefore it should have been allowed for a single act to result in multiple convictions if those acts constituted separate criminal violations according to established law.