Appellate Review of Sentences. The Sentencing Reform Act of 1984 requires that challenges to sentences be made on direct appeal. Generally, a sentencing court may revise a sentence only on remand after a successful appeal. In a narrowset of circumstances, however, a sentence may be reviewed and modified by the sentencing court itself. A sentencing court may stay a sentence if the sentence or conviction is appealed. A defendant may waive their right to appeal a sentence by plea agreement if the waiver is knowing and voluntary.

The government or the defendant may appeal a sentence that either party believes is unreasonable. In Rita v. United States, the Supreme Court held that circuit courts may establish a presumption of reasonableness for sentences within the range recommended by the Sentencing Guidelines. Regardless of whether a sentence falls within the Guidelines, it is deferentially reviewed on appeal under the abuse-of-discretion standard.

A sentence may be appealed on the grounds that it was imposed in violation of law, resulted from an incorrect application of the Sentencing Guidelines, is plainly unreasonable for an offense for which no Guideline has been established, or includes a greater fine or term of imprisonment, probation, or supervised release than the maximum specified in the applicable Guideline. An appellate court has jurisdiction to review a sentencing court's refusal to depart from the applicable Guidelines range if the sentencing court erred in concluding that it did not have discretionary authority to depart.

The government, with the personal approval of the Attorney General, the Solicitor General, or a Deputy Solicitor General, also may appeal a sentence under certain circumstances.

If the appellate court finds a sentence unreasonable on one of the above grounds, and the error is not harmless, the court must remand the case with any instructions it deems appropriate.

If the defendant or government fails to raise an alleged sentencing error at the time of sentencing, the claim will be reviewable on appeal only for plain error. An appellate court determines whether the error is plain at the time of the appeal, regardless of whether a legal question was unsettled at the time of trial. Even if the alleged sentencing error is plain, an appellate court may still affirm the sentence if the error does not “seriously affect[] the fairness, integrity or public reputation of judicial proceedings.”