In Montgomery v. United States, the Supreme Court considered the case of a man who had been convicted of violating the Indian Major Crimes Act. The defendant, Montgomery, had been convicted of murdering a Native American on a reservation in Arizona. Montgomery argued that the Major Crimes Act was unconstitutional because it violated the Fifth Amendment's guarantee of due process. The Supreme Court held that the Major Crimes Act was constitutional. The Court reasoned that Congress had the power to regulate Indian affairs and that the Major Crimes Act was a valid exercise of that power. The Court also held that the Major Crimes Act did not violate the Fifth Amendment's guarantee of due process because it provided for a fair trial and the right to appeal. The Court's decision in Montgomery v. United States established that Congress had the power to regulate Indian affairs and that the Major Crimes Act was a valid exercise of that power. The decision also established that the Major Crimes Act did not violate the Fifth Amendment's guarantee of due process.

Justice Field delivered the dissenting opinion in Montgomery v. United States, arguing that Congress had exceeded its authority by passing a law which allowed for the punishment of an individual who was not convicted of any crime. He argued that this violated both due process and equal protection under the law as guaranteed by the Fifth Amendment to the Constitution. Additionally, he noted that while Congress has broad powers when it comes to regulating commerce between states, they do not have unlimited power over individuals within those states. Justice Field concluded his dissent by noting that if such laws were allowed to stand then there would be no limit on what Congress could pass in terms of punishing people without trial or conviction - something which is clearly unconstitutional and should never be tolerated.