Prime minister

An executive arm of government, usually in a parliamentary or semi-presidential system, is led by the prime minister, who is the head of the cabinet and the leader of the ministers. In those systems, a prime minister is neither the head of state nor the monarch of their respective state; rather, the prime minister is the head of government, serving typically under a monarch in a hybrid of aristocratic and democratic government forms or a president in a republican government form, depending on the system.

According to the Westminster system, the prime minister is the presiding and real head of government, as well as the head of the executive branch, in parliamentary systems modelled after the Westminster system. For example, under monarchical or presidential systems, the head of state or their official representative (such as a royal family or a governor-general) often retains only ceremonial responsibilities, but they may have reserve powers in certain cases.

In certain presidential systems, such as those in South Korea and Peru, the prime minister is not the head of government; rather, he or she is simply the leader of the cabinet or the most senior member of the cabinet in these countries.

A prime minister chooses and may dismiss other members of the cabinet, and he or she also distributes positions to members of the government in various systems. In most systems, the prime minister serves as both the presiding member and the chairman of the government cabinet. As the person responsible for managing the civil service and carrying out the instructions issued by the head of state under a small number of governments, particularly semi-presidential systems of government, a prime minister may be chosen in certain countries.