How Do Appeals Work? What a Higher Court Can and Cannot Change

The division of labour in a legal system is that trial courts find facts and appeal courts check law. The trial judge or jury saw the witnesses, weighed the documents and decided what happened, and an appeal court will not disturb those findings unless no reasonable tribunal could have reached them. What it will examine is whether the law was applied correctly: whether the judge misdirected the jury, admitted evidence that should have been excluded, misread a statute, or imposed a sentence outside the permitted range.

That is why an appeal is argued from transcripts and written submissions rather than testimony, and why fresh evidence is almost never allowed. The rule in most systems is that new evidence is admitted only if it could not have been obtained for the trial with reasonable diligence and would probably have changed the outcome. A witness who has changed their mind, or a document the losing side simply failed to find, does not qualify.

In civil cases either side can usually appeal, though many systems now require permission from either the trial judge or the appeal court, granted only if the appeal has a real prospect of success. In criminal cases the defendant can appeal against conviction, sentence or both. The prosecution's right to appeal an acquittal is much more limited, because of the rule against double jeopardy: in the United States it barely exists, and in England it was extended in 2003 only for serious offences where compelling new evidence emerges.

Time limits are short and strict, typically 21 or 28 days from the judgment, and an appeal does not automatically halt the judgment's effect. A civil award may have to be paid unless a stay is granted, and a convicted defendant normally remains in custody while the appeal is heard.

Appeals move up a hierarchy, and each step is harder to take. In England and Wales a case tried in the Crown Court goes to the Court of Appeal, and from there, only on a point of law of general public importance and with permission, to the Supreme Court, which hears fewer than a hundred cases a year. In the United States a federal case goes from a district court to one of thirteen circuit courts of appeals, whose decision is final unless the Supreme Court chooses to take it; it receives around seven thousand requests a year and grants roughly one percent.

The top court in each system exists less to correct individual injustices than to settle what the law is. Its decisions bind every lower court, so a single appeal can change how thousands of future cases are decided, which is why appeal courts publish reasoned judgments and trial courts mostly do not.

An appeal court has a limited menu. It can affirm, leaving the decision as it stands, which is the most common result. It can reverse, substituting its own decision where the law permits, for instance by quashing a conviction that rested on inadmissible evidence. It can vary, reducing a sentence or adjusting an award of damages. Or it can remit, sending the case back to the lower court to be decided again under the correct rules, which in a criminal case may mean a retrial before a new jury.

A successful appeal does not necessarily mean the appellant was right on the merits. A conviction quashed for a procedural error may be followed by a retrial and a second conviction. Conversely, an appeal court will let a flawed trial stand if the error made no difference, under what is called the harmless error rule: the question is always whether the mistake could have affected the result. The grounds that succeed most often:

• •The judge misdirected the jury on the law or the burden of proof
• •Evidence was admitted that the rules of evidence exclude, or excluded that they allow
• •A statute or precedent was misinterpreted
• •The sentence fell outside the lawful or guideline range
• •The procedure denied one side a fair hearing

A system that allowed every losing party a complete rehearing would double the cost and length of every case and would give the party with more money an extra chance at everything. Confining appeals to errors of law keeps the trial as the place where facts are decided, by the people who saw the evidence, and makes the appeal court a check on the process rather than a repeat of it. It also means that an appeal has to be prepared during the trial: an objection not raised when the evidence came in is usually lost, because the appellant cannot complain of a ruling they never asked for.

An appeal asks a higher court to correct an error of law in a decision, not to retry the facts, which is why it is argued from the record and rarely admits new evidence. Permission and time limits gate it, the prosecution's rights are narrower than the defendant's, and the possible outcomes are to affirm, reverse, vary or send the case back to be decided again properly.