A prime minister, in government, the highest-ranking member of the council of ministers, or cabinet, the body of executives who in parliamentary systems set policy for and supervise the departments of government. The term "prime minister" is used in Great Britain and nations formerly in the British Empire, including members of the Commonwealth of Nations. In most European countries the prime minister is called "premier." However, in West Germany the title "chancellor" is used. In the Soviet Union the prime minister is known officially as the chairman of the council of ministers.
A prime minister may come to power in two main ways. In the Soviet Union he and the other ministers are elected by the supreme soviet, or national legislature. In the more widely used parliamentary system, legislative approval is also required but the prime minister is first asked to take the position by the head of state, whether a president, as in India or Italy, a monarch, as in Great Britain or Denmark, or a governor general representing the monarch, as in Canada, Australia, or New Zealand.
The powers of a prime minister vary with the system of government his country has. In parliamentary government modeled on the British system, where the post of prime minister first developed in the 18th century, the prime minister is leader of the majority party or of a coalition of parties in the legislature. The head of state exercises little power, and it is left to the prime minister to lead his party in parliament, supervise the work of the ministries, and lead in formulating his government's domestic and foreign policy. He is assisted by his cabinet, a group of legislators whom he has selected to head the major ministries and who meet with him frequently to formulate policy. The prime minister exercises control over the cabinet, for he decides what will be discussed at cabinet meetings and he may replace any minister. The prime minister also has the power to call for unscheduled general elections whenever he thinks that new elections will increase his majority in the legislature. Generally a prime minister remains in office for the full term of the legislature. However, the prime minister is responsible to the legislature, and if it votes no confidence in his administration, the prime minister and his government must resign and new elections must be held.
Under the French system the premier has fewer powers and a different relation to the legislature. The president has so many powers that the prime minister is chiefly a coordinator of the work of the various ministries. Legislative and executive power are separated, and the prime minister and his ministers may not at the same time be members of the lawmaking body.
Finally, as a general rule a prime minister is always responsible ultimately to the legislature. The notable exception to this rule is the strong monarchy that existed until 1974 in Ethiopia, where the prime minister was responsible to the emperor rather than to the parliament.