On January 7, 2013, a three-judge panel of the U.S. Court of Appeals for the Ninth Circuit issued its decision in United States v. Juan. As a matter of first impression, the Ninth Circuit held that the constitutional proscription on substantial governmental interference with defense witnesses also applies to prosecution witnesses. By extending the “substantial interference” rule to prosecution witnesses, Juan fundamentally, albeit implicitly, recognized a Sixth Amendment Confrontation Clause aspect of the “substantial interference” rule. Moreover, future application of Juan may require that courts consider the propriety of a factfinder receiving evidence about any governmental actions that potentially caused a prosecution witness to “alter” his or her testimony. Ultimately, given the strong potential of Juan-type situations to occur in future prosecutions, courts will have ample opportunity to further analyze and refine the Juan rule’s prohibition on substantial govern-mental interference with prosecution witnesses.