Preservation of Rights for Review. An appellate court will generally review an issue only if the appellant made a specific, timely objection at or before trial or sentencing (the “contemporaneous objection” rule). If an objection was not made, an appellate court will review the issue under the limited “plain error”standard. The contemporaneous objection requirement applies to both the government and the defendant. In trials with multiple defendants, the circuits are split on whether to limit objections to the defendant who raised the issue. Failure to comply with a state's contemporaneous objection rule may preclude federal habeas review.

Evidentiary objections and jury-instruction objections are specifically addressed in statutory rules governing the preservation of error for review. Additionally, federal rules require certain objections to be raised by pretrial motion. These include defects in the institution of the prosecution, defects in the indictment, suppression of evidence, discovery requests, and requests for severance. The circuits are split on whether the issue of unconstitutional vagueness can be raised for the first time on appeal. The contemporaneous objection rule applies to prosecutorial misconduct, judicial misconduct, sentencing errors, juror bias, and other trial errors. Claims of ineffective assistance of counsel must be preserved by an objection at trial unless special circumstances exist. A party must also make a timely, though not necessarily contemporaneous, objection to the contents of a magistrate's report.

In addition to raising specific objections at the proper time, a defendant generally must continue to assert the objections throughout the trial to preserve the issues for appeal. A motion in limine generally does not preserve a claim for appellate review. Although many guilty pleas include an express waiver or limitation on the defendant's right to appeal, Rule 11(a)(2) of the Federal Rules of Criminal Procedure permits a defendant to enter a conditional guilty plea, reserving in writing the right to appeal specified pretrial motions and withdraw the plea if the appeal is successful. Additionally, the contemporaneous objection rule does not apply to lack of subject-matter jurisdiction, when an objection at trial would have been futile or baseless under then-existing law, or when the defendant was ignorant of the facts supporting the claim raised on appeal.