Hierarchy of Authority

Hierarchy of Authority

Courts exist in a hierarchical structure.  In both State and federal jurisdictions, there are district courts, appeals courts, and supreme courts.⁵  District courts are the first courts to hear cases, and they are the only courts that make use of juries.  District courts are expected to follow the legal precedents set by higher courts (appeals courts and supreme court), and their primary role is to make findings of fact.

Appeals courts are the next level up.  They hear a fraction of cases in which the decision or procedure of the district court was arguably flawed in some way.  Appeals courts rarely, if ever, second-guess the factual findings of district courts -- their job is to decide questions of law, not fact.  If the fact-finding procedure of the district court was flawed in some way, the appeals court may order a new trial at the district level.  Otherwise, the appeals court judges will take as given the facts found by the district court and apply their findings of law to those facts. 
A supreme court is the highest court of appeals in a jurisdiction.  When the decisions of appeals courts are appealed, they go to the supreme court.  The judges who sit on the supreme court have discretion to decide which cases they will hear.  Typically, some fraction of the judges (in the case of the US Supreme Court, 4 out of 9 Justices) must vote in favor of hearing a case; this is called granting certiorari, or "cert" for short.  When a supreme court makes a ruling, its decision is considered a binding precedent for all lower courts in its jurisdiction. 
Each State has its own supreme court.  The US Supreme Court is the supreme court of the federal court system.  It hears appeals from US Circuit Courts of Appeals, as well as some special courts such as the US military courts.  In addition, the US Supreme Court may hear appeals from State supreme courts on decisions that rely on the US Constitution or federal law.