572 U.S. 65 (2014)
Rosemond v. United States is a cornerstone Supreme Court decision at the intersection of accomplice liability and federal firearms law.
Does a conviction for aiding and abetting a violation of 18 U.S.C. § 924(c) require proof that the defendant had advance knowledge that a confederate would use or carry a firearm during and in relation to the predicate drug trafficking crime or crime of violence?
A defendant is liable for aiding and abetting under 18 U.S.C. § 2 only if he takes an affirmative act in furtherance of the offense with the intent of facilitating its commission. For a § 924(c) offense (use or carry of a firearm during and in relation to a predicate crime), the government must prove the accomplice (1) actively participated in the underlying predicate crime and (2) had advance knowledge that a confederate would use or carry a firearm in the commission of that crime—knowledge obtained at a time when the accomplice could realistically withdraw or otherwise refrain from further participation.
Yes. To convict a defendant of aiding and abetting a § 924(c) offense, the government must show that the defendant actively participated in the underlying predicate crime with advance knowledge that a confederate would use or carry a firearm. Because the jury instructions did not require the jury to find such advance knowledge, the conviction was vacated and the case remanded.
Rosemond is a leading case on accomplice liability and mens rea for compound federal crimes. It firmly establishes that for § 924(c) aiding-and-abetting liability, the government must prove not just participation in the predicate crime, but also timely knowledge of the firearm sufficient to allow withdrawal. The decision shapes federal jury instructions, charging decisions, and plea negotiations in gun-related drug and violence prosecutions. For law students, it illustrates how courts import general principles of accomplice liability into specific statutory frameworks, how timing of knowledge affects intent, and how the Court calibrates criminal culpability when aggravating elements (like a gun) transform the offense.