Judges must decide cases based on the applicable law. In some cases a judge may be asked to declare that a certain law is unconstitutional. Judges have the power to rule that a law is unconstitutional and therefore void, but they must give
proper deference to the legislative body that enacted the law.

There are two types of judges: trial court and appellate. Trial court judges preside over trials, usually from beginning to end. They decide pretrial motions, define the scope of discovery, set the trial schedule, rule on oral motions during trial, control the behavior of participants and the pace of the trial, advise the jury of the law in a jury trial, and sentence a guilty defendant in a criminal case.