By the Constitution, the government of the USA is composed of three branches: the legislative, the executive, and the judicial.
The legislative power belongs to the Congress consisting of 2 chambers: the Senate and the House of Representatives. The Senate is composed of 2 members from each state elected for a term of 6 years, one third being elected every 2 years. The number of representatives from each state depends on the population of the state, each state having at least one representative. The members of the House of Representatives are elected for 2 years.
In order to become a law, all bills and resolutions must pass both the Houses and be signed by the President.
The executive branch of the government is headed by the President who is elected for a term of 4 years by electors of each state. One of the functions of the President is to appoint Federal judges.
The head of the judicial branch of power and the highest judicial body of the United States is the Supreme Court. The Supreme Court judges – they are normally nine, but Congress may alter their number – are nominated for life by the President after being approved by the Senate. The Supreme Court has the power of judicial review – the power to decide whether the actions of the President, Congress or state governments violate the Constitution.
The judicial systems of the states vary greatly in structure and procedure. Yet, there is a certain hierarchy of courts. In all states magistrate courts are at the lowest level. They deal with minor offences. Then come county courts which deal with the majority of civil and criminal cases. Appeals go to the District Courts of Appeals.
In more than two-thirds of the states, judges are elected.