The functions exercised by a president vary according to the form of government. In parliamentary and semi-presidential republics, they are limited to those of the head of state, and are thus largely ceremonial. In presidential republics, the role of the president is more prominent, encompassing also (in most cases) the functions of the head of government. In authoritarian regimes, a dictator or leader of a one-party state may also be called a president, often charismatically.
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), but today it most commonly refers to an executive official in any social organization. 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" in the United States (one of the roles constitutionally assigned to the vice president). 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.
In pre-revolutionary France, the president of a Parlement evolved into a powerful magistrate, a member of the so-called noblesse de robe (" nobility of the gown"), with considerable judicial as well as administrative authority. The name referred to his primary role of presiding over trials and other hearings. In the 17th and 18th centuries, seats in the Parlements, including presidencies, became effectively hereditary, since the holder of the office could ensure that it would pass to an heir by paying the crown a special tax known as the paulette . The post of "first president" ( premier président ), however, could only be held by the King's nominees. The Parlements were abolished by the French Revolution. In modern France the chief judge of a court is known as its president ( président de la cour ).
The first usage of the word president to denote the highest official in a government was during the Commonwealth of England. After the abolition of the monarchy the English Council of State, whose members were elected by the House of Commons, became the executive government of the Commonwealth. The Council of State was the successor of the Privy Council, which had previously been headed by the Lord President ; its successor the Council of State was also headed by a Lord President, the first of which was John Bradshaw. However, the Lord President alone was not head of state, because that office was vested in the council as a whole.
The modern usage of the term president to designate a single person who is the head of state of a republic can be traced directly to the United States Constitution of 1787, which created the office of President of the United States. Previous American governments had included "presidents" (such as the president of the Continental Congress or the president of the Massachusetts Provincial Congress), but these were presiding officers in the older sense, with no executive authority. It has been suggested that the executive use of the term was borrowed from early American colleges and universities, which were usually headed by a president. British universities were headed by an official called the " Chancellor " (typically a ceremonial position) while the chief administrator held the title of " Vice-Chancellor ". But America's first institutions of higher learning (such as Harvard University and Yale University) didn't resemble a full-sized university so much as one of its constituent colleges. A number of colleges at Cambridge University featured an official called the "president". The head, for instance, of Magdalene College, Cambridge was called the master and his second the president. The first president of Harvard, Henry Dunster, had been educated at Magdalene. Some have speculated that he borrowed the term out of a sense of humility, considering himself only a temporary place-holder. The presiding official of Yale College, originally a "rector" (after the usage of continental European universities), became "president" in 1745.
A common style of address for presidents, " Mr/Mrs. President," is borrowed from British Parliamentary tradition, in which the presiding Speaker of the House of Commons is referred to as "Mr/Mrs. Speaker." Coincidentally, this usage resembles the older French custom of referring to the president of a parlement as " Monsieur/Madame le Président ", a form of address that in modern France applies to both the President of the Republic and to chief judges. Similarly, the Speaker of the Canadian House of Commons is addressed by francophone parliamentarians as " Monsieur/Madame Président(e) ". In Pierre Choderlos de Laclos's novel Les Liaisons Dangereuses of 1782, the character identified as Madame la Présidente de Tourvel ("Madam President of Tourvel") is the wife of a magistrate in a parlement . The fictional name Tourvel refers not to the parlement in which the magistrate sits, but rather, in imitation of an aristocratic title, to his private estate.
Once the United States adopted the title of "president" for its republican head of state, many other nations followed suit. Haiti became the first presidential republic in Latin America when Henri Christophe assumed the title in 1807. Almost all of the American nations that became independent from Spain in the early 1810s and 1820s chose a US-style president as their chief executive. The first European president was the president of the Italian Republic of 1802, a client state of revolutionary France, in the person of Napoleon Bonaparte. The first African president was the President of Liberia (1848), while the first Asian president was the President of the Republic of China (1912).
In the twentieth and twenty-first centuries, the powers of presidencies have varied from country to country. The spectrum of power has included presidents-for-life and hereditary presidencies to ceremonial heads of state.
Presidents in the countries with a democratic or representative form of government are usually elected for a specified period of time and in some cases may be re-elected by the same process by which they are appointed, i.e. in many nations, periodic popular elections. The powers vested in such presidents vary considerably. Some presidencies, such as that of Ireland, are largely ceremonial, whereas other systems vest the president with substantive powers such as the appointment and dismissal of prime ministers or cabinets, the power to declare war, and powers of veto on legislation. In many nations the president is also the commander-in-chief of the nation's armed forces, though once again this can range from a ceremonial role to one with considerable authority.
In almost all states with a presidential system of government, the president exercises the functions of head of state and head of government, i.e. the president directs the executive branch of government. When a President not only is head of state, but also head of government, is this, in Europe known to be a President of Counsel From the French Présidente du Conseil , used 1871-1940 and 1944-1958, as the Third and Fourth French Republics. In the United States has the President always been both Head of State and Head of Government and has always had the title of President.
Presidents in this system are either directly elected by popular vote or indirectly elected by an electoral college or some other democratically elected body.
In the United States, the President is indirectly elected by the Electoral College made up of electors chosen by voters in the presidential election. In most states of the United States, each elector is committed to voting for a specified candidate determined by the popular vote in each state, so that the people, in voting for each elector, are in effect voting for the candidate. However, for various reasons the numbers of electors in favour of each candidate are unlikely to be proportional to the popular vote. Thus, in five close United States elections ( 1824, 1876, 1888, 2000, and 2016), the candidate with the most popular votes still lost the election.
In Mexico, the president is directly elected for a six-year term by popular vote. The candidate who wins the most votes is elected president even without an absolute majority. The president may never get another term. The 2006 Mexican elections had a fierce competition, the electoral results showed a minimal difference between the two most voted candidates and such difference was just about the 0.58% of the total vote. The Federal Electoral Tribunal declared an elected president after a controversial post-electoral process.
In Brazil, the president is directly elected for a four-year term by popular vote. A candidate has to have more than 50% of the valid votes. If no candidates achieve a majority of the votes, there is a runoff election between the two candidates with most votes. Again, a candidate needs a majority of the vote to be elected. In Brazil, a president cannot be elected to more than two consecutive terms, but there is no limit on the number of terms a president can serve.
A second system is the semi-presidential system, also known as the French model. In this system, as in the parliamentary system, there are both a president and a prime minister; but unlike the parliamentary system, the president may have significant day-to-day power. For example, in France, when his party controls the majority of seats in the National Assembly, the president can operate closely with the parliament and prime minister, and work towards a common agenda. When the National Assembly is controlled by his opponents, however, the president can find himself marginalized with the opposition party prime minister exercising most of the power. Though the prime minister remains an appointee of the president, the president must obey the rules of parliament, and select a leader from the house's majority holding party. Thus, sometimes the president and prime minister can be allies, sometimes rivals; the latter situation is known in France as cohabitation. Variants of the French semi-presidential system, developed at the beginning of the Fifth Republic by Charles de Gaulle, are used in France, Portugal, Romania, Sri Lanka and several post-colonial countries which have emulated the French model. In Finland, although the 2000 constitution moved towards a ceremonial presidency, the system is still formally semi-presidential, with the President of Finland retaining e.g. foreign policy and appointment powers.
The parliamentary republic, is a parliamentary system in which the presidency is largely ceremonial with either de facto or no significant executive authority (such as the President of Austria) or de jure no significant executive power (such as the President of Ireland), and the executive powers rests with the Prime Minister who automatically assumes the post as head of a majority party or coalition, but takes oath of office administered by the president. However, the president is head of the civil service, commander in chief of the armed forces and can dissolve parliament. Countries using this system include Austria, Albania, Bangladesh, Czech Republic, Germany, Greece, Hungary, Iceland, India, Ireland, Israel, Italy,  Malta, Pakistan, Singapore.
A variation of the parliamentary republic is a system with an executive president in which the president is the head of state and the government but unlike a presidential system, is elected by and accountable to a parliament, and referred to as president. Countries using this system include Botswana, South Africa and Suriname.
Only a tiny minority of modern republics do not have a single head of state. Some examples of this are:
- Switzerland, where the headship of state is collectively vested in the seven-member Swiss Federal Council, although there is also a President of the Confederation, who is a member of the Federal Council elected by the Federal Assembly (the Swiss Parliament) for a year ( constitutional convention mandates that the post rotates every New Year's Day).
- The Captains Regent of San Marino elected by the Grand and General Council.
- In the former Soviet Union, while the real power was exercised by the general secretary of the Communist Party, the Presidium of the Supreme Soviet executed powers of collective head of state, and its chairman was often called "president" in the West.
- Yugoslavia after the death of Josip Broz Tito until its breakup.
- Presidency of Bosnia and Herzegovina
- National Council of Government (Uruguay)
- Junta of National Reconstruction in Nicaragua
In dictatorships, the title of president is frequently taken by self-appointed or military-backed leaders. Such is the case in many states: Idi Amin in Uganda, Mobutu Sese Seko in Zaire, Ferdinand Marcos in Philippines and Saddam Hussein in Iraq are some examples. Other presidents in authoritarian states have wielded only symbolic or no power such as Craveiro Lopes in Portugal and Joaquín Balaguer under the "Trujillo Era" of the Dominican Republic.
President for Life is a title assumed by some dictators to try to ensure that their authority or legitimacy is never questioned. Ironically, most leaders who proclaim themselves President for Life do not in fact successfully serve a life term. On the other hand, presidents like Alexandre Pétion, Rafael Carrera, Josip Broz Tito and François Duvalier died in office. Kim Il-sung was named Eternal President of the Republic after his death.
In ancient Rome, Lucius Cornelius Sulla appointed himself in 82 BC to an entirely new office, dictator rei publicae constituendae causa ("dictator for the making of laws and for the settling of the constitution"), which was functionally identical to the dictatorate rei gerundae causa ("for the matter to be done," e.g., a military command against a specific enemy) except that it lacked any set time limit, although Sulla held this office for over two years before he voluntarily abdicated and retired from public life.
The second well-known incident of a leader extending his term indefinitely was Roman dictator Julius Caesar, who made himself " Perpetual Dictator " (commonly mistranslated as 'Dictator-for-life') in 45 BC. His actions would later be mimicked by the French leader Napoleon Bonaparte who was appointed "First Consul for life" in 1802.
Several presidents have ruled until their death, but they have not proclaimed themselves as President for Life. For instance, Nicolae Ceauşescu of Romania, who ruled until his execution (see Romanian Revolution).
As the country's head of state, in most countries the president is entitled to certain perquisites, and may have a prestigious residence, often a lavish mansion or palace, sometimes more than one (e.g. summer and winter residences, or a country retreat) Customary symbols of office may include an official uniform, decorations, a presidential seal, coat of arms, flag and other visible accessories, as well as military honours such as gun salutes, ruffles and flourishes, and a presidential guard. A common presidential symbol is the presidential sash worn most often by presidents in Latin America and Africa as a symbol of the continuity of the office. 
United Nations member countries in columns, other entities at the beginning:
- European Commission
- List of presidents of European Union institutions
- List of Presidents of the Soviet Union ( Leaders)
Titles for non-heads of state
As head of government
Some countries with parliamentary systems use a term meaning/translating as "president" (in some languages indistinguishable from chairman) for the head of parliamentary government, often as President of the Government, President of the Council of Ministers or President of the Executive Council.
However, such an official is explicitly not the president of the country . Rather, he/she is called a president in an older sense of the word, to denote the fact that he/she heads the cabinet . A separate head of state generally exists in their country that instead serves as the president or monarch of the country.
Thus, such officials are really premiers, and to avoid confusion are often described simply as 'prime minister' when being mentioned internationally.
There are several examples for this kind of presidency:
- The official title of the Italian Prime Minister is President of the Council of Ministers ( Italian Presidente del Consiglio dei Ministri )
- Under the French Third and the Fourth Republics, the " President of the Council " (of ministers – or prime minister) was the head of government, with the President of the Republic a largely symbolic figurehead.
- The Prime minister of the Irish Free State from 1922 to 1937 was titled President of the Executive Council of the Irish Free State. At the same time, the Irish Free State was a constitutional monarchy with a reigning monarch, the King of Ireland, as well as a resident Governor-General carrying out many head of state functions.
- Under the constitutional monarchies of Brazil and Portugal, the President of the Council of Ministers ( Portuguese Presidente do Conselho de Ministros ) was the head of government, with the Monarch being the head of State. Under the Portuguese First and Second Republics, the head of government was the President of the Ministry ( Portuguese Presidente do Ministério ) and then the President of the Council of Ministers, with the President of the Republic as the head of State.
- The Prime Minister of Spain is officially referred to as the President of the Government of Spain, and informally known as the "president". Spain is also a kingdom with a reigning king.
- The official title of the Croatian prime minister is President of the Government of the Republic of Croatia ( Croatian: Predsjednik Vlade Republike Hrvatske ).
- The official title of the Polish prime minister is President of the Council of Ministers ( Polish Prezes Rady Ministrów ).
- In British constitutional practice, the chairman of an Executive Council, acting in such a capacity, is known as a President of the Executive Council. Usually this person is the Governor and it always stays like that.
- Between 1918 and 1934, Estonia had no separate head of state. Both Prime Ministers (1918-1920) and State Elders (1920-1934) often translated as "Presidents") were elected by the parliament.
Other executive positions
President can also be the title of the chief executive at a lower administrative level, such as the parish presidents of the parishes of the U.S. state of Louisiana, the presiding member of city council for villages in the U.S. state of Illinois, or the municipal presidents of Mexico's municipalities. Perhaps the best known sub-national presidents are the borough presidents of the Five Boroughs of New York City.
In Poland the President of the City ( Polish: Prezydent miasta ) is the executive authority of the municipality elected in direct elections, the equivalent of the mayor. The Office of the President (Mayor) is also found in Germany and Switzerland.
Governors of ethnic republics in the Russian Federation used to have the title of President, occasionally alongside other, secondary titles such as Chairman of the Government (also used by Prime Minister of Russia). This likely reflects the origin of Russian republics as homelands for various ethnic groups: while all federal subjects of Russia are currently de jure equal, their predecessors, the ASSRs, used to enjoy more privileges than the ordinary krais and oblasts of the RSFSR (such as greater representation in the Soviet of Nationalities). Thus, the ASSRs and their eventual successors would have more in common with nation-states than with ordinary administrative divisions, at least in spirit, and would choose titles accordingly.
Over the course of the 2010s the presidents of Russian republics would progressively change their title to that of Head ( Russian: глава ), a proposition suggested by the President of Chechnya Ramzan Kadyrov and later made law by the Parliament of Russia and President Dmitriy Medvedev in 2010. Despite this, however, Presidents of Tatarstan would reject this change and, as of 2017, retain their title in defiance of Russian law. The new title did not result in any changes in the powers wielded by the governors.
The Lord President of the Council is one of the Great Officers of State in England who presides over meetings of British Privy Council ; the Cabinet headed by the Prime Minister is technically a committee of the Council, and all decisions of the Cabinet are formally approved through Orders in Council. Although the Lord President is a member of the Cabinet, the position is largely a ceremonial one and is traditionally given to either the Leader of the House of Commons or the Leader of the House of Lords.
Historically the President of the Board of Trade was a cabinet member.
In Spain, the executive leaders of the autonomous communities (regions) are called presidents. In each community, they can be called Presidente de la Comunidad or Presidente del Consejo among others. They are elected by their respective regional assemblies and have similar powers to a state president or governor.
Below a president, there can be a number of or "vice presidents" (or occasionally "deputy presidents") and sometimes several "assistant presidents" or "assistant vice presidents", depending on the organisation and its size. These posts do not hold the same power but more of a subordinate position to the president. However, power can be transferred in special circumstances to the deputy or vice president. Normally vice presidents hold some power and special responsibilities below that of the president. The difference between vice/deputy presidents and assistant/associate vice presidents is the former are legally allowed to run an organisation, exercising the same powers (as well as being second in command) whereas the latter are not.
In some countries the speaker of their unicameral legislatures, or of one or both houses of bicameral legislatures, the speakers have the title of president of "the body".
In French legal terminology, the president of a court consisting of multiple judges is the foremost judge; he chairs the meeting of the court and directs the debates (and this thus addressed as "Mrs President", "Madame la Présidente", Mr President", or Monsieur le Président . In general, a court comprises several chambers, each with its own president; thus the most senior of these is called the "first president" (as in: "the First President of the Court of Cassation is the most senior judge in France"). Similarly in English legal practice the most senior judge in each division uses this title (e.g. President of the Family Division, President of the Court of Appeal).
In the recently established Supreme Court of the United Kingdom, the most senior judge is called the President of the Supreme Court. The Lady/Lord President of the Court of Session is head of the judiciary in Scotland, and presiding judge (and Senator) of the College of Justice and Court of Session, as well as being Lady/Lord Justice General of Scotland and head of the High Court of Justiciary, the offices having been combined in 1784.
- Mr. President (title)
- Presidents Day
- Presidential system
- Requirements for becoming a president
- Vice president
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