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Case Basics
Docket No. 
Justus C. Rosemond
United States
(for the petitioner)
(Assistant to the Solicitor General, Department of Justice, for the respondent)
Facts of the Case 

In August 2007, Justus Rosemond and Ronald Joseph met Ricardo Gonzalez in a Tooele, Utah, park to sell him a pound of marijuana. When Gonzalez attempted to take the marijuana without paying, he was fired upon while fleeing. The government charged Justus Rosemond with several drug- and firearm-related offenses. At trial, the government alleged that Rosemond was either the shooter or that he aided and abetted the shooter. The jury convicted Rosemond on all charges.On appeal, Rosemond argued that the trial court’s instructions to the jury regarding the aiding and abetting theory were insufficient and that the jury must find that Rosemond “intentionally took some action to facilitate or encourage the use of a firearm” to convict. The Tenth Circuit affirmed Rosemond’s conviction.


Does the offense of aiding and abetting the use of a firearm during a drug trafficking crime require proof of the defendant’s intentional facilitation or encouragement of the use of the firearm in order to convict?

Decision: 9 votes for Rosemond, 0 vote(s) against
Legal provision: §924(c) of Title 18

Yes. Justice Elena Kagan delivered the opinion for the 7-2 majority. The Court held that the government must prove that the defendant actively participated in a drug or violent crime intending to see it succeed and knew in advance that one of his coconspirators had a gun during the crime. Whether the defendant approved or disapproved of having or using the gun is irrelevant, as long as he participated in the underlying drug or violent crime with knowledge of a gun. Proof that the defendant knew that a gun was used sometime in the commission of the crime is insufficient; if, as in this case, a defendant learns of a gun upon seeing or hearing an accomplice fire shots after the criminal scheme has begun, he cannot be held liable for aiding and abetting under this statute. The State must prove as part of the knowledge element that the accomplice had the opportunity to walk away after learning of the gun but chose to proceed thereby incurring the liability of this statute.

Justice Samuel A. Alito, Jr. wrote an opinion concurring in part and dissenting in part, disagreeing only with the majority’s new rule that the State prove that the aider and abetter had an opportunity to refrain from the criminal conduct after learning of a gun. His dissent rests on the position that this requirement deviates from the traditional aiding and abetting doctrine, and it opens up the affirmative defense of necessity or duress for the accomplice that does not object to having a gun for fear violence might be directed at him. Justice Clarence Thomas joined in the partial concurrence and partial dissent.

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ROSEMOND v. UNITED STATES. The Oyez Project at IIT Chicago-Kent College of Law. 03 September 2015. <>.
ROSEMOND v. UNITED STATES, The Oyez Project at IIT Chicago-Kent College of Law, (last visited September 3, 2015).
"ROSEMOND v. UNITED STATES," The Oyez Project at IIT Chicago-Kent College of Law, accessed September 3, 2015,