A judge is an elected or appointed official who conducts court proceedings in civil disputes (usually involving money or property) and in criminal prosecutions (in which a person or entity has been charged with a crime). Judges must be impartial and strive to properly interpret the meaning and application of the law.

In criminal prosecutions (cases), 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 for them. The judge also sets the amount of bail. Once the defendant has an attorney and the bail amount has been set, the defendant 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 a jury is present. In most serious criminal cases a jury is present and is thus the trier of fact—meaning that the jury looks at the evidence presented to the court and determines what actually happened and whether the defendant is guilty. In these cases, the judge is the trier of law—meaning the judge ensures that everything happening in the courtroom follows the rules of law.

If a party in a civil or criminal case has not requested a jury, or is not entitled to a jury, the judge becomes both the trier of fact and the trier of law. This is more common in civil cases in which there is a relatively small amount of money in dispute—but in criminal cases it happens only if both the state and the defendant agree in writing not to have a jury trial.

Judges may also determine the defendant’s sentence or punishment in criminal cases, and in some civil cases, judges determine the amount of sanctions, penalties, or damages.

In South Dakota, judges play a critical role in both civil and criminal court proceedings. They are responsible for ensuring the impartial application of the law and overseeing the legal process. In criminal cases, a South Dakota judge must initially determine if there is sufficient evidence to believe a crime has been committed and that the accused is likely responsible. If the accused cannot afford an attorney, the judge is required to appoint one. The judge also sets bail and ensures that any plea entered by the defendant is voluntary. In trials with a jury, the judge acts as the trier of law, guiding the legal proceedings and interpreting the law, while the jury serves as the trier of fact, determining guilt or innocence based on the evidence. If there is no jury, the judge assumes both roles. This scenario is more common in civil cases with smaller monetary disputes and in criminal cases only if both the prosecution and defense waive the right to a jury trial in writing. Additionally, judges in South Dakota are tasked with sentencing in criminal cases and may determine financial penalties in civil matters.