D was a member of a gang that controlled the sale of crack cocaine in a southside Minneapolis neighborhood. At trial, D was found guilty on seven charges some of which included carrying a firearm during drug trafficking. At sentencing, the District Court made an error. For the first §924(c) offense, the court imposed a 5-year sentence. It rejected P's request for the 25-year minimum prescribed in §924(c)(1)(C) for “second or subsequent” offenses and imposed the 10-year term prescribed in §924(c)(1)(A)(iii) for first-time offenses. The total sentence came to 442 months. D appealed contending that the appropriate total sentence for all his crimes was 15 years. P did not appeal or cross-appeal. P made the observation that the sentence was 15 years too short only to counter D’s argument that it was unreasonably long. P simply urged that D’s sentence should be affirmed. Relying on the “plain-error rule” in 52(b) the appeals court held that it had discretion to raise and correct the District Court’s error on its own initiative. It vacated the sentence and instructed the District Court “to impose the [statutorily mandated] consecutive minimum sentence of 25 years.” The Supreme Court granted certiorari.