Presidential system

A presidential system is a system of government that features a president as the nation's head of state and active chief executive authority. The term is usually used in contrast to a parliamentary system.

Differences with a parliamentary system

A number of key theoretical differences exist between a presidential and a parliamentary system:

In a presidential system, the central principle is that the legislative and executive branches of government should be separate. This leads to the separate election by the electorate or an electoral college of the president, who is elected to office for a fixed term of office, and only removable in extreme cases for gross misdeamour by impeachment and dismissal. In addition he or she does not need to choose cabinet members from or commanding the support of, a legislative majority. By contrast, in parliamentary systems, government is usually carried out by a cabinet headed by a Prime Minister who in many instances are members of parliament (legislature), are directly accountable to parliament and may by parliamentary vote be dismissed.
As with the President's set term of office, the legislature also exists for a set term of office and cannot be dissolved ahead of schedule. By contrast, in many parliamentary systems, parliament can be dissolved at any stage during its term of office by the head of state, usually on the advice of the Prime Minister, by the Prime Minister and cabinet, or by the cabinet.
In a presidential system, the president usually has special privileges in the enactment of legislation, namely the possession of a power of veto over legislation of bills, in some cases subject to the power of the legislature by weighed majority to override the veto. However, it is extremely rare for the president to have the power to directly propose laws, or cast a vote on legislation. The legislature and the president are thus expected to serve as a check on each other's powers.

The reality

In reality, elements of both systems overlap. Though a president in a presidential system does not have to choose a government answerable to the legislature, it may have the right to scrutinise his or her appointments to high governmental office, with the right on occasion to block an appointment. In the United States, many appointments must be confirmed by the Senate. By contrast, though answerable to parliament, a parliamentary system's cabinet may be able to make use of the parliamentary 'whip' (an obligation on party members in parliament to vote with their party) to control and dominate parliament, reducing its ability to control the government.

Presidential governments also make no distinction between the positions of Head of state and Head of government, both of which are held by the president. While many parliamentary governments have a symbolic president or monarch whose constitutional prerogatives may generally be exercised by the Prime Minister, presidents in presidential systems are always active participants in the political process, and never symbolic figureheads, though the extent of their relative power or powerlessness may be influenced by the political makeup of the legislature, and whether their supporters or opponents are dominant therein. In some presidential systems such as South Korea or the Republic of China (on Taiwan), there is an office of the prime minister or premier, but unlike semi-presidential or parliamentary systems, the premier is responsible to the president rather than to the legislature.

In the late nineteenth century, it was speculated that the United States Speaker of the House of Representatives would evolve into a quasi-prime minister, with the US system evolving into a form of parliamentarianism. However this did not happen. More recently, it has been suggested that the office of White House Chief of Staff, the President's chief aide, has become a de facto United States prime minister of sorts, with his dominance or weakness in the US governmental system depending on whether there is a "hands off" or "hands on" president. (Ronald Reagan was the former, Bill Clinton the latter). Reagan's Chiefs of Staff in many ways ran the day to day affairs of government, with the President standing back from intervention.

Countries with Presidential systems include the United States, Mexico, and most nations in South America.