Courts in the United States are reluctant to re-examine or reopen cases already decided on by another court. The legal system in place is made to allow those that feel they have been wronged by the judicial system to have their grievances reheard by an appellate court but the courts themselves have a reluctant attitude to retrial cases that have already been decided.
The appeals process allows a losing party in a trial court decision to have their case re-tried again. Some decisions by federal administrative agencies are also subject to appeals. Both parties are able to appeal in a civil case, but the government is prohibited from appealing not guilty verdicts in criminal cases. However, either party may appeal the sentence issued in the case of a guilty verdict. Bankruptcy appeals in some districts may be handled by a separate appellate committee of bankruptcy judges.