A judge is an elected or appointed official who conducts court proceedings. Judges must be impartial and strive to properly interpret the meaning, significance, and implications of the law. Judges must also recognize that justice means more than just interpreting the law — they must also show compassion and understanding for the people on both sides of the case.

When a case first comes to the court, the judge must decide whether there is enough evidence to support a reasonable belief that a crime has occurred and also that the person in question committed that crime. If the defendant cannot afford to hire a lawyer, the judge must appoint a lawyer to them. The judge also sets the bail. Once the defendant has an attorney and his or her bail amount has been set, he or she enters a plea of guilty or not guilty. The judge must ensure that the plea has been made voluntarily.

The role of a judge during a hearing depends on whether or not a jury is present. In most serious criminal cases, a jury is present and thus it is the trier of fact, meaning that the jury looks at the evidence presented to the court and determines what actually happened and whether or not the defendant is guilty. The judge is the trier of law, meaning he or she ensures that everything happening in the courtroom follows the rules set down by the law. If a jury is not present in a court case, the judge becomes both the trier of fact and the trier of law. This is typical for civil cases, but in criminal cases it happens only if both the state and the defendant agree in writing to not have a jury trial, so minor criminal cases are the most likely to have bench trials. Judges also determine the sentence in criminal cases and the fine amount in civil cases.

Judges have different responsibilities in juvenile cases, because juveniles cannot be charged with crimes due to their diminished responsibility. Because the court is not a criminal court, the proceedings are not adversarial and therefore the juvenile does not get a jury trial. Instead, the judge listens to the evidence and arguments on both sides of the case and decides what would be best for the juvenile, the community, and the legal system.

Judges are also responsible for signing warrants for arrests and searches. In common-law legal systems such as the one used in the United States, judges have the power to punish misconduct occurring within a courtroom, to punish violations of court orders, and to enforce an order to make a person refrain from doing something. Judges in this type of system can declare a law unconstitutional, as long as the reason is applicable to the case at hand. In addition, judges are able to go against precedent, which provides some flexibility to interpretation of the law.