The justice system in the US is unique. It consists of two separate sovereign court systems, state and federal, that peacefully coexist under the concept of federalism (in which sovereignty is divided between a central governing authority and constituent political units). The justice system in Pennsylvania is even more unique in that only four of the fifty United States are organized and recognized as "commonwealths," a federated union of local government constituents.
Most criminal laws that govern day to day life are state sponsored. Federal crimes are those committed across state lines (e.g. kidnapping or evading arrest) or those perpetrated against the United States government (e.g. treason, fraud, income tax evasion).
There are two types of trials, criminal and civil. A civil trial is a dispute between two parties. A criminal trial (this website is dedicated solely to criminal law) involves the government or some unit of the government prosecuting an individual for an offense prohibited by statutory law or common law (case or judicial law). Usually, criminal trials involve actions taken as the result of malicious intent, although cases of extreme negligence (such as a drunk driver killing a pedestrian) can also be considered criminal.
Although each state is free to arrange its own court system (within the parameters of the Constitution), most states' justice systems have common hierarchal structures, most often reflecting the framework of the United States Judicial System.
Pennsylvania is divided into 60 judicial districts, most of which have magisterial district judges (formerly called district justices and justices of the peace). These Judges preside mainly over minor criminal offenses and small civil claims. Philadelphia also has a separate traffic court which hears cases involving motor vehicle violations within the city.
The general trial courts in which most criminal and civil cases originate are the Courts of Common Pleas. They also serve as appellate courts (courts of appeal) to the district judges and for local agency decisions. The Courts of Common Pleas serving the larger Pennsylvania counties are divided into specialized divisions.
Pennsylvania has two intermediate-level appellate courts: the Superior Court and the Commonwealth Court. If either the Defendant or the Commonwealth feels that the Courts of Common Pleas judge made an error in his rulings (e.g. including or excluding evidence, making a bad call on an objection, etc.) they can appeal to these courts. The fifteen judges of the Superior Court hear all the appeals from the Courts of Common Pleas that are not expressly designated to the Commonwealth Court or Supreme Court. It also has original jurisdiction (The original jurisdiction of a court refers to matters on which that court is the first one allowed to try the case) to grant or deny warrants for wiretap surveillance. The jurisdiction of the nine-judge Commonwealth Court can only hear appeals from final orders of certain state agencies and certain designated cases from the Courts of Common Pleas. It is important to remember that whereas trials are focused upon the testimony of witnesses and other evidence concerning a Defendant's actions or observations, appeals feature two lawyers (a criminal defense attorney-unless the appeal is taken by the Defendant his or herself) prosecuting or district attorney) attempting to convince a panel of judges that a mistake was made and that case and statutory law is on their side. Attorneys prepare written briefs citing historical rulings and prepare a legal argument to persuade the judges to rule in their favor. If unsatisfied with the appellate ruling, a party can ask for an appeal the Pennsylvania Supreme Court.
Pennsylvania's entire judicial system is under the supervision of the Supreme Court of Pennsylvania. The Supreme Court makes the Rules of the Court. It is also the final appellate court for both the Superior Court and the Commonwealth Court. It may hear appeals directly from the Courts of Common Pleas in certain cases, including murder convictions in which the death penalty has been imposed, criminal contempt, and any case in which the Court of Common Pleas ruled that a state law was unconstitutional. Like all judges in Pennsylvania, the seven justices of the Supreme Court are chosen by public election; the Chief Justice is the justice with the most seniority.
Only when an appellant (the person appealing the decision) has exhausted all his options in the State Courts may he or she file a writ of certiorari (request to be heard) to the United States Supreme Court. Unless the legal issue is one involving federal or constitutional clarification or interpretation, the Supreme Court will most likely decline to hear the appeal.
Pennsylvania's Unified Judicial System forms a hierarchal structure that can best be illustrated in the form of a pyramid, as presented below:

On the federal level, Article III of the United States Constitution establishes the judicial branch as one of the three branches of federal government. The other two branches are the legislative and executive. Federal courts, the guardians of the Constitution, protect rights guaranteed by the Constitution. Congress, not the Courts, make laws. Federal courts resolve disputes by interpreting and applying laws. Only the President and executive branch departments and agencies have the power to enforce the laws. The courts do not have this power.
The US judicial power is vested in one Supreme Court and a lower court system as established by Congress. The system is arranged with intermediate appellate courts "courts of appeals," and trial courts, "district courts." Thirteen courts of appeals serve 12 geographic regions. Pennsylvania federal appeals are heard in the Third Circuit. All Federal judges serve for life, unless they resign, die or are removed by congressional impeachment.
The 94 US District Courts in 50 states and US dependent territories hear cases allowed under the Constitution and federal law where crimes violate federal laws or disputes between citizens of different states (civil). Above the district courts; the 13 Circuit Courts of Appeal only hear district court appeals on issues of law and questions legal interpretation. Circuit Court rulings are appealed to the United States Supreme Court, the highest court of the land.
The Federal Judiciary may also be illustrated in terms of a pyramid, as shown below. The High Court is the U.S. Supreme Court.
