In Koons v. United States, after several criminal defendants pleaded guilty to drug conspiracy charges, the district court discovered that the mandatory minimum sentence provided under 21 U.S.C. sec. 841(b)(1) was higher than the sentencing range provided under the Sentencing Guidelines. The district court decided that the mandatory minimums trumped the Guidelines, and sentenced the defendants under that range, although the judge lowered the ultimate sentence after accounting for other mitigating factors. The Guidelines were later amended to lower the sentencing range for drug conspiracies, and the defendants moved to reduce their sentences under 18 U.S.C. sec. 3582(c)(2). The Court, in a unanimous opinion by Justice Alito, affirmed the lower courts and held that the defendants were not entitled to relief because their sentences were not based on the Guidelines, which is a prerequisite for relief under Section 3582(c)(2).