A "not guilty" verdict on all charges normally ends a criminal case—the prosecution cannot appeal an acquittal. A guilty verdict on some or all charges, however, doesn't necessarily mean the case is over. Defendants who think they've been wrongfully convicted can:
An appeal is a request to a higher (appellate) court to review and change the decision of a lower court. The defendant may challenge the conviction itself or the sentence (without attacking the underlying conviction). A successful appeal usually restores a case to the initial stages, but can sometimes end the case altogether (such as when the appellate court finds that there's insufficient evidence to retry the defendant).
The typical hierarchy of state courts consists of:
The same general hierarchy exists in federal courts, with the highest federal court being the U.S. Supreme Court.
Convicted defendants generally have a right to review by an intermediate appellate court, provided that they comply with statutory time limits for requesting an appeal. Some appeals—in misdemeanors and infraction cases, for example—may go to the appellate division of a superior court.
Defendants file written "briefs" (which often are far from brief) claiming that certain errors warrant reversal of a conviction or at least reduction of a sentence. After the government submits a responding brief, an appellate court may hear oral arguments from both sides. Weeks and sometimes months later, the appellate court issues a written decision upholding or reversing a conviction.
If a state's intermediate appellate court upholds a conviction, a defendant can appeal to the state's highest court and then to the U.S. Supreme Court. However, the higher appellate courts (the "supreme" courts) have discretionary jurisdiction, which means that they can decide not to review a case.
The government cannot appeal verdicts of acquittal. However, if a trial judge rules that a convicted defendant is entitled to a new trial, the government can appeal the new trial order. (For an exception about the appealability of acquittals, see our article on acquittals by judges in jury trials.
Appellate courts most often review only legal claims that defendants have made at trial. If defendants neglect to make legal claims at trial, they usually waive those claims. For example, if a defendant asks an appellate court to reverse a conviction because of the prosecutor's unfair argument, the court will probably consider the point only if the defense objected to the argument during the trial.
Not every error at trial merits reversal. The general rule is that defendants are entitled to a fair trial, not an error-free trial. (Lutwak v. U.S., 344 U.S. 604 (1953).) Appellate courts generally don't reverse convictions unless a legal error was likely to have contributed to a guilty verdict. However, errors involving constitutional rights require reversal, normally unless appellate courts determine that they were "harmless" beyond a reasonable doubt.
Even when upholding convictions, appellate courts can review sentences. For example, an appellate court might uphold a conviction but reduce the sentence by 30 days if the trial judge neglected to credit the defendant with the month that the defendant spent in jail prior to trial. (For more in this area, see our article on appealing a sentence.)
Defendants who plead guilty can appeal. But the grounds for appeal are generally very limited. For example, a defendant can appeal and his conviction may be set aside if his attorney failed to advise him of the effect of a guilty plea on his immigration status. (Padilla v. Kentucky, 559 U.S. 356 (2010).) Other kinds of ineffective legal representation can be grounds for challenging a conviction, even when the defendant has pleaded guilty. (For more on appealing after a guilty plea, see our article on conditional pleas. For information on undoing a plea, read about withdraw a guilty plea)
If you've been convicted of a crime and want to challenge the conviction or sentence, consult an experienced criminal appellate lawyer. Appellate lawyers have special expertise regarding the appeals process and can provide a neutral analysis of your chances.