The judicial branch makes sure that laws are followed correctly. It consists of the Supreme Court, which is the highest (most important) court, and 13 circuit courts.
The justices, or judges, on the Supreme Court interpret the Constitution, which means they decide how it applies in specific situations.
There are eight associate justices on the Supreme Court and one chief justice. The justices are appointed by presidents, and they serve until they retire or die.
The Supreme Court reviews cases that have been tried and decided in a lower court. Usually, the losing side in a case appeals to the Supreme Court. In general, the court hears only cases that have to do with federal law or the Constitution.