The rules governing federal criminal appeals can be found in 18 U.S.C. § 3732. A federal appeal is governed under different procedures than a normal trial; it is sent to an appellate court that reviews the transcripts of the court proceedings and the briefs (initial legal documents) prepared by both sides and then makes a determination as to the trial’s legality. However, the appellate court does not make a guilty or innocent determination. Instead, it looks for legal errors; on occasion, a criminal proceeding is reversed or dismissed outright. Errors can be found that do not reverse the outcome of the case; however, constitutional errors usually result in verdict reversal.
The Federal Rules of Appellate Procedure lay out the rules for federal criminal appeals. The process is usually quite lengthy and will involve long briefs, document and trial transcript review, and oral arguments. Federal appellate courts do not hear actual witness testimony during their case; instead, they read the briefs, any documentation, and sometimes hear oral arguments before rendering a decision.
Every defendant in the United States court system has the right to an appeal. However, some criminals waive this right when they cut plea bargains with federal attorneys. A guilty plea automatically waives the right to a federal criminal appeal.