In the case of William Freeman v. United States in 2010, the Supreme Court was asked to determine whether a defendant who enters into a plea agreement is eligible for sentence reduction when sentencing guidelines are later lowered. The petitioner, William Freeman, had been sentenced to prison under mandatory minimums as part of his plea deal but sought relief after changes were made to crack cocaine sentencing policies that would have reduced his term. The government argued that because he agreed to specific terms in a plea bargain, he could not seek further reductions. The court ruled 5-4 in favor of Freeman with Justice Kennedy writing the majority opinion and stating that defendants who enter into plea agreements should be able to benefit from retroactive changes in sentencing guidelines if their sentences are based on those guidelines. This ruling allows prisoners like Freeman an opportunity for sentence reduction even after entering into a binding agreement with prosecutors.

In the dissenting opinion for William Freeman v. United States, Justice Sotomayor argued that a defendant's eligibility for sentence reduction under 18 U.S.C §3582(c)(2) should be determined by whether the sentencing range was lowered by the Sentencing Commission after their initial sentencing. She disagreed with the majority’s interpretation of “based on” in this context and contended that it should refer to all sentences influenced or informed by a Guidelines range, not just those strictly within such a range. The justice also expressed concern over potential unfairness and inconsistency resulting from different interpretations of plea agreements across various courts. Furthermore, she believed that allowing district courts to revisit old sentences would undermine finality in criminal cases and burden judicial resources unnecessarily.