A scrap metal and junk dealer, Morissette (defendant), entered an Air Force bombing range and took several spent bomb casings that had been lying around for years exposed to the weather and rusting. Morissette subsequently flattened the casings out and sold them for an $84 profit. Morissette was indicted for violating 18 U.S.C. § 641 which made it a crime to “knowing convert” government property. At trial, Morissette admitted he knew he was taking Air Force property but honestly believed the government had abandoned the casings. The trial judge rejected Morissette’s defense and instructed the jury that “[t]he question on intent is whether or not he intended to take the property.” Morissette was convicted and he appealed. The court of appeals affirmed and made the assumption that Congress meant for the term “knowingly convert” to mean simply an intentional exercise of dominion over property not belonging to the individual. The U.S. Supreme Court granted certiorari to review.