Socialist International
The Socialist International (SI) is a worldwide organisation of political parties which seek to establish democratic socialism. It consists mostly of democratic socialist, social-democratic and labour political parties and other organisations.

Although formed in 1951 as a successor to the Labour and Socialist International, it has antecedents to the late 19th century. The organisation currently includes 147 member parties and organisations from over 100 countries. Its members have governed in many countries including most of Europe.

The current secretary general of the SI is  (Chile) and the current president of the SI is the former Prime Minister of Greece, George Papandreou, both of whom were re-elected at the last SI Congress held in Cartagena, Colombia in March 2017.

History

First and Second Internationals (1864–1916)
The International Workingmen's Association, also known as the First International, was the first international body to bring together organisations representing the working class. It was formed in London on 28 September 1864 by socialist, communist and anarchist political groups and trade unions. Tensions between moderates and revolutionaries led to its dissolution in 1876 in Philadelphia.

The Second International was formed in Paris on 14 July 1889 as an association of the socialist parties. Differences over World War I led to the Second International being dissolved in 1916.

Labour and Socialist International (1919–1940)
The International Socialist Commission (ISC), also known as the Berne International, was formed in February 1919 at a meeting in Berne by parties that wanted to resurrect the Second International. In March 1919 communist parties formed Comintern (the Third International) at a meeting in Moscow.

Parties which did not want to be a part of the resurrected Second International (ISC) or Comintern formed the International Working Union of Socialist Parties (IWUSP, also known as Vienna International/Vienna Union/Two-and-a-Half International) on 27 February 1921 at a conference in Vienna. The ISC and the IWUSP joined to form the Labour and Socialist International (LSI) in May 1923 at a meeting in Hamburg. The rise of Nazism and the start of World War II led to the dissolution of the LSI in 1940.

Socialist International (1951–present)
The Socialist International was formed in Frankfurt in July 1951 as a successor to the LSI.

During the post-World War II period, the SI aided social democratic parties in re-establishing themselves when dictatorship gave way to democracy in Portugal (1974) and Spain (1975). Until its 1976 Geneva Congress, the SI had few members outside Europe and no formal involvement with Latin America. In the 1980s, most SI parties gave their backing to the Nicaraguan Sandinistas (FSLN), whose democratically-elected left-wing government was subject to a campaign to overthrow it backed by the United States, which culminated in the Iran–Contra affair after the Reagan administration covertly continued US support for the Contras after such support was banned by Congress.

In the late 1970s and in the 1980s the SI had extensive contacts and discussion with the two leading powers of the Cold War period, the United States and the Soviet Union, on issues concerning East–West relations and arms control. The SI supported détente and disarmament agreements, such as SALTII, START and INF. They had several meetings and discussion in Washington, D.C. with President Jimmy Carter and Vice-President George Bush and in Moscow with Secretaries General Leonid Brezhnev and Mikhail Gorbachev. The SI's delegations to these discussions were led by the Finnish Prime Minister Kalevi Sorsa.

Since then, the SI has admitted as members an increasing number of parties and organisations from Africa, Asia, Europe and Latin America (see below for current list).

Following the Tunisian revolution, the Constitutional Democratic Rally was expelled from the SI in January 2011; later that month the Egyptian National Democratic Party was also expelled; and as a result of the 2010–2011 Ivorian crisis, the Ivorian Popular Front was expelled in March 2011, in accordance with section 7.1 of the statutes of the Socialist International. These decisions were approved at the subsequent SI Congress in Cape Town in 2012 in line with section 5.1.3 of the statutes.

Progressive Alliance (2013)
Despite the carrying out of open, transparent, fully democratic elections overseen by an electoral committee headed by the Social Democratic Party of Germany (SPD) at the 2012 SI Congress, on 22 May 2013 the SPD along with some other current and former member parties of the SI founded a rival international network of social-democratic parties known as the Progressive Alliance, citing their perceived undemocratic and outmoded nature of the SI, as well as the Socialist International's admittance and continuing inclusion of undemocratic political movements into the organization.

Relationship with Latin America 
For a long time, the Socialist International remained distant from Latin America, considering the region as a zone of influence of the United States. For example, it does not denounce the coup d'état against Socialist President Jacobo Arbenz in Guatemala in 1954 or the invasion of the Dominican Republic by the United States in 1964. It was not until the 1973 Chilean coup d'état that we discovered "a world we did not know", explains Antoine Blanca, a diplomat for the French PS. According to him, solidarity with the Chilean left was "the first challenge worthy of the name, against Washington, of an International which, until then, had done everything to appear subject to American strategy and NATO". Subsequently, notably under the leadership of François Mitterrand, the SI supported the sandinistas in Nicaragua and other movements in El Salvador, Guatemala and Honduras in their struggle against US-supported dictatorships.

In the 1990s, it was joined by non-socialist parties that took note of the economic power of the European countries governed or to be governed by their partners across the Atlantic and calculated the benefits they could derive from it. During this period, "the socialist international works in a clientist way; some parties come here to rub shoulders with Europeans as if they were in the upper class," says Porfirio Muñoz Ledo, one of the representatives of the Party of the Democratic Revolution (Mexico) at the SI. It is home to "the very centrist Argentinean Radical Civic Union (UCR); the Mexican Institutional Revolutionary Party (PRI), which was not very democratically in power for seventy years; the Colombian Liberal Party - under whose governments the left-wing formation Patriotic Union (1986-1990) was exterminated - introduced the neoliberal model (1990-1994) and to which, until 2002, Alvaro Uribe will belong". In the following decade, many left-wing parties that came to power (in Brazil, Venezuela, Bolivia, Ecuador and El Salvador) preferred to keep their distance from the SI.

Presidents, honorary presidents and secretaries general

Presidents
 Morgan Phillips, United Kingdom (1951–1957)
 Alsing Andersen, Denmark (1957–1962)
 Erich Ollenhauer, West Germany (1963)
 Bruno Pittermann, Austria (1964–1976)
 Willy Brandt, West Germany (1976–1992)
 Pierre Mauroy, France (1992–1999)
 António Guterres, Portugal (1999–2005)
 George Papandreou, Greece (2006–present)

Honorary presidents
Current and honorary presidents include:
 Pierre Mauroy, former president of the SI
Mustapha Ben Jaafar, Tunisia
Leonel Brizola, Brazil
 Ruben Berrios, Puerto Rico
 Philippe Busquin, Belgium
 Cuauhtémoc Cárdenas, Mexico
 Mohamed El Yazghi, Morocco
 Alan García, Peru
 Anita Gradin, Sweden
 Elazar Granot, Israel
Tarja Halonen, Finland
Mahamadou Issoufou, Niger
 Anker Jørgensen, Denmark
 Lionel Jospin, France
 Neil Kinnock, Great Britain
Horacio Serpa, Colombia
 Enrique Silva Cimma, Chile
 Mário Soares, Portugal
 Hans-Jochen Vogel, Germany

Secretaries general
 Julius Braunthal, Austria (1951–1956)
 Bjarne Braatoy, Norway (1956–1957)
 Albert Carthy, Great Britain (1957–1969)
 Hans Janitschek, Austria (1969–1976)
 Bernt Carlsson, Sweden (1976–1983)
 Pentti Väänänen, Finland (1983–1989)
 , Chile (1989–present)

Summits
 I  Frankfurt 1951
 II  Milan 1952
 III  Stockholm 1953
 IV  London 1955
 V  Vienna 1957
 VI  Hamburg 1959
 VII  Rome 1961
 VIII  Amsterdam 1963
 IX  Brussels 1964
 X  Stockholm 1966
 XI  Eastbourne 1969
 XII  Vienna 1972
 XIII  Geneva 1976
 XIV  Vancouver 1978
 XV  Madrid 1980
 XVI  Albufeira 1983
 XVII  Lima 1986
 XVIII  Stockholm 1989
 XIX  Berlin 1992
 XX  New York 1996
 XXI  Paris 1999
 XXII  São Paulo 2003
 XXIII  Athens 2008
 XXIV  Cape Town 2012
XXV  Cartagena 2017

Members

Full members
The following parties are full members:

Consultative parties
The following parties are consultative parties:

Observer parties
The following parties are observer parties:

Former members

Fraternal organisations
 International Falcon Movement – Socialist Educational International
 International Union of Socialist Youth
 Socialist International Women

Associated organisations