Presidential system

A presidential system is a system of government where a head of government is also head of state and leads an executive branch that is separate from the legislative branch. The United States, for instance, have a presidential system. The executive is elected and often titled "president" and is not responsible to the legislature and cannot, in normal circumstances, dismiss it. The legislature may have the right, in extreme cases, to dismiss the executive, often through impeachment. However, such dismissals are seen as so rare as not to contradict a central tenet of presidentialism, that in normal circumstances using normal means the legislature cannot dismiss the executive.

The title president has persisted from a time when such person personally presided over the government body, as with the US President of the Continental Congress, before the executive function was split into a separate branch of government and could no longer preside over the legislative body.

Presidential systems are numerous and diverse, but the following are generally true:

Prime minister

A prime minister is the most senior minister of cabinet in the executive branch of government, often in a parliamentary or semi-presidential system. In many systems, the prime minister selects and may dismiss other members of the cabinet, and allocates posts to members within the government. In most systems, the prime minister is the presiding member and chairman of the cabinet. In a minority of systems, notably in semi-presidential systems of government, a prime minister is the official who is appointed to manage the civil service and execute the directives of the head of state.

In parliamentary systems fashioned after the Westminster system, the prime minister is the presiding and actual head of government and head of the executive branch. In such systems, the head of state or the head of state's official representative (i.e. the monarch, president, or governor-general) usually holds a largely ceremonial position, although often with reserve powers.

The prime minister is often, but not always, a member of parliament and is expected with other ministers to ensure the passage of bills through the legislature. In some monarchies the monarch may also exercise executive powers (known as the royal prerogative) that are constitutionally vested in the crown and may be exercised without the approval of parliament.

Parliamentary system

A parliamentary system is a system of democratic governance of a state in which the executive branch derives its democratic legitimacy from, and is held accountable to, the legislature (parliament); the executive and legislative branches are thus interconnected. In a parliamentary system, the head of state is normally a different person from the head of government. This is in contrast to a presidential system in a democracy, where the head of state often is also the head of government, and most importantly, the executive branch does not derive its democratic legitimacy from the legislature.

Countries with parliamentary systems may be constitutional monarchies, where a monarch is the ceremonial head of state while the head of government is almost always a member of the legislature (such as the United Kingdom, Sweden and Japan), or parliamentary republics, where a mostly ceremonial president is the head of state while the head of government is regularly from the legislature (such as Ireland, Germany, India and Italy). In a few parliamentary republics, such as Botswana, South Africa and Suriname, as well as German states, the head of government is also head of state, but is elected by and is answerable to the legislature.

President

A president is the leader of a country or a division or part of a country, typically a republic, a democracy, or a dictatorship. The title "president" is sometimes used by extension for leaders of other groups, including corporate entities.

Etymologically, a president is one who presides (from Latin prae- "before" + sedere "to sit"; giving the term praeses). Originally, the term referred to the presiding officer of a ceremony or meeting (i.e., chairman), but today it most commonly refers to an executive official. Among other things, "President" today is a common title for the heads of state of most republics, whether presidential republics, semi-presidential republics or parliamentary republics.

Title

The title President is derived from the Latin prae- "before" + sedere "to sit." As such, it originally designated the officer who presides over or "sits before" a gathering and ensures that debate is conducted according to the rules of order (see also chairman and speaker). Early examples are from the universities of Oxford and Cambridge (from 1464) and the founding President of the Royal Society William Brouncker in 1660. This usage survives today in the title of such offices as "President of the Board of Trade" and "Lord President of the Council" in the United Kingdom, as well as "President of the Senate" (one of the roles constitutionally assigned to the Vice-President of the United States). The officiating priest at certain Anglican religious services, too, is sometimes called the "President" in this sense. However the most common modern usage is as the title of a head of state in a republic.