[JURIST] The US Supreme Court [official website] ruled [opinion, PDF] Wednesday in Rosemond v. United States [SCOTUSblog backgrounder] that defendants have to know in advance that their accomplices would use or carry a gun while committing a crime in order to be convicted under federal gun laws. Justus Rosemond was charged, among other things, for using a gun in connection with a drug trafficking charge, or aiding and abetting that offense in violation of 18 USC §§ 924(c)(1)(A) and 2 [text]. At trial, a federal jury convicted and sentenced Rosemond to 14 years. The Court took up Rosemond’s case to determine whether the aiding and abetting charge requires proof of intentional facilitation or encouragement of the use of a firearm, or simple knowledge that the principal used a firearm during a drug trafficking crime in which the defendant also participated. In resolving the circuit split, the majority found that intent is critical: “the § 924(c ) defendant’s knowledge of a firearm must be advance knowledge—or otherwise said, knowledge that enables him to make the relevant legal (and indeed, moral choice),” Justice Elena Kagan wrote.

When an accomplice knows beforehand of a confederate’s design to carry a gun, he can attempt to alter that plan, or in unsuccessful, withdraw from the enterprise; it is deciding instead to go ahead with his role in the venture that shows his intent to aid an armed offense. But when an accomplice knows nothing of a gun until it appears at the scene, he may already have completed his acts of assistance; or even if not, he may at that late point have no realistic opportunity to quit the crime. And when that is so, the defendant has not shown the requisite intent to assist a crime involving a gun.

Justice Samuel Alito, joined by Justice Clarence Thomas, filed a partial dissent, accusing the the majority of confusing the concepts of intent and motive:

[The Court] seems to assume that, if a defendant’s motive in aiding a criminal venture is to avoid some greater evil, he does not have the intent that the venture succeed. But the intent to undertake some act is of course perfectly consistent with the motive of avoiding adverse consequences which would otherwise occur.

By converting what has been an affirmative defense into a part of the required mens rea, Alito argued that the court “fundamentally alters the prior understanding of mental states that form the foundation of substantive criminal law, and places a strange and difficult burden on the prosecution.”