United States v. Haynes is a United States Supreme Court case that addressed the issue of whether a person who had been convicted of a crime and had served their sentence could be required to register a firearm they owned. The case involved a man named Haynes who had been convicted of a felony in Texas and had served his sentence. After his release, he was found to be in possession of a firearm and was charged with violating the National Firearms Act of 1934, which required individuals convicted of a crime to register any firearms they owned. Haynes argued that the Act was unconstitutional because it violated his Fifth Amendment right against self-incrimination. The Supreme Court ultimately ruled in favor of the United States, finding that the National Firearms Act did not violate the Fifth Amendment. The Court reasoned that the Act did not require Haynes to incriminate himself, as he was already convicted of a crime and the registration of the firearm was not a criminal act. The Court also noted that the registration of firearms was necessary to ensure public safety and that the Act was a reasonable exercise of Congress' power to regulate interstate commerce. As such, the Court held that the National Firearms Act was constitutional and that Haynes was required to register his firearm.

In United States v. Haynes, the Supreme Court was tasked with determining whether a convicted felon could be required to register a firearm he had acquired prior to his conviction. The majority opinion held that Congress did not have the power under the Second Amendment or any other provision of law to require such registration and thus affirmed the lower court's decision in favor of Haynes. Justice Harlan dissented from this ruling, arguing that Congress has broad authority over interstate commerce and can therefore regulate firearms as it sees fit. He further argued that while individuals may possess firearms for personal use without registering them, they cannot do so if their possession is part of an activity which affects interstate commerce - such as selling guns across state lines or using them in criminal activities - since these activities are subject to congressional regulation under its Commerce Clause powers. Therefore, according Harlan's dissent, requiring felons who acquire firearms before their convictions to register those weapons does not violate either the Second Amendment or any other constitutional provision; rather it is simply an exercise of Congress' legitimate authority over matters affecting interstate commerce