[JURIST] The US Supreme Court [official website; JURIST news archive] on Monday ruled [opinion, PDF] unanimously in United States v. O'Brien [Cornell LII backgrounder] that the question of whether a firearm is a machine gun must be proved to the jury beyond a reasonable doubt and is not a sentencing factor to be considered by the judge by a preponderance of the evidence. The court held that the type of firearm used in perpetrating a crime was an element of the crime under mandatory minimum sentencing guidelines. The government had attempted to extend the sentence of the respondents under 18 USC s. 924(c) [text], which sets a mandatory minimum sentence of 30 years for using a machine gun during a crime. The US Court of Appeals for the First Circuit ruled [opinion, PDF] that such a determination should be made by a jury. In doing so, the court relied on statutory interpretation outlined by the Supreme Court in Castillo v. United States [opinion, PDF; Cornell LII backgrounder] in interpreting a previous version of s. 924(c), creating a circuit split. The First Circuit held that the amendment to the statute had not altered the holding of Castillo. In upholding the decision below, Justice Anthony Kennedy explained:

Th[e] structural or stylistic change … does not provide a "clear indication" that Congress meant to alter its treatment of machineguns as an offense element. A more logical explanation for the restructuring is that it broke up a lengthy principal paragraph, which exceeded 250 words[,] … into a more readable statute. This is in step with current legislative drafting guidelines, which advise drafters to break lengthy statutory provisions into separate subsections that can be read more easily. … These points are overcome, however, by the substantial weight of the other Castillo factors and the principle that Congress would not enact so significant a change without a clear indication of its purpose to do so. The evident congressional purpose was to amend the statute to … make [it] more readable but not otherwise to alter the substance of the statute. The analysis and holding of Castillo control this case. The machinegun provision in [s.] 924(c)(1)(B)(ii) is an element of an offense.

Justice John Paul Stevens filed a concurring opinion, and Justice Clarence Thomas filed an opinion concurring in the judgment only.

Respondents Martin O'Brien and Arthur Burgess made a failed attempt to rob an armored car in 2005, using a firearm that the FBI alleged had been modified to operate as a fully-automatic weapon. The court heard oral arguments [transcript, PDF; JURIST report] in February. Counsel for the petitioner, the US government, argued that the language of the statute requires a judge to make the determination. Counsel for the respondents argued that such a result is foreclosed by the Supreme Court's statutory interpretation jurisprudence.