The powers of the judicial departments of the state and federal governments are exercised by courts provided for in their respective constitutions or created by the legislative departments for the purpose of exercising such judicial powers. The general functions of courts and the apportionment of powers among them will be considered later. In describing the organization of such departments for present purposes, it is sufficient to say that courts are presided over by judges; and that these judges are selected by election or appointment, as may be provided in the state or federal constitution, respectively. In England the judges are appointed by or under the authority of the king, and the term of office is unlimited. In some of the older states the judges are appointed by the executive, in others they are elected by the state legislatures. In much the larger number of states, however, judges, like legislative or executive officers, are chosen by a popular election for fixed terms. But the desirability of securing the complete independence of the judiciary and removing the judges from all party influence was a sufficient argument with the framers of the federal constitution to induce them to provide that the judges of the federal courts shall hold office during good behavior and receive a compensation which shall not be diminished during their continuance in office (Art. III, § 1). This means that they are appointed for life and can be removed only by impeachment. Their appointment is by the president, by and with the advice and consent of the Senate (Art. II, § 2, ¶ 2).

Even in the states in which the judges are elected there has been a tendency to secure independence of party influences by providing for long terms, or for choice at an election distinct from that at which other state and federal officers are elected, or by continuing the incumbents in office by repeated re-elections.