Centre-left politics in the context of "Green politics"

The Progressive Alliance of Socialists and Democrats (S&D) is the political group in the European Parliament of the Party of European Socialists (PES). The Progressive Alliance of Socialists and Democrats was officially founded as a Socialist Group on 29 June 1953, which makes it the second oldest political group in the European Parliament after the European People's Party Group (EPP Group). It adopted its present-day name on 23 June 2009. Centre-left in orientation, the group mostly comprises social democratic parties and is affiliated with the Progressive Alliance and Socialist International.

Until the 1999 European Parliament elections, it was the largest group in the Parliament, but since then it has always been the second-largest group. During the eighth EU Parliament Assembly, the S&D was the only Parliament group with representation from all 27 EU member states. In the current EU Parliament the S&D is currently composed of 136 members from 25 member states.

The Australian Labor Party (ALP), also known as the Labor Party or simply Labor, is the major centre-left political party in Australia and one of two major parties in Australian politics, along with the centre-right Liberal Party of Australia. The party has been in government since the 2022 federal election, and with political branches active in all the Australian states and territories, they currently hold government in New South Wales, South Australia, Victoria, Western Australia, and the Australian Capital Territory. As of 2025, Queensland, Tasmania and Northern Territory are the only states or territories where Labor currently forms the opposition. It is the oldest continuously operating political party in Australian history, having been established on 8 May 1901 at Parliament House, Melbourne, the meeting place of the first Federal Parliament.

The ALP is descended from the labour parties founded in the various Australian colonies by the emerging labour movement. Colonial Labour parties contested seats from 1891, and began contesting federal seats following Federation at the 1901 federal election. In 1904, the ALP briefly formed what is considered the world's first labour party government and the world's first democratic socialist or social democratic government at a national level. At the 1910 federal election, Labor became the first party in Australia to win a majority in either house of the Australian parliament. In every election since 1910 Labor has either served as the governing party or the opposition. There have been 13 Labor prime ministers and 10 periods of federal Labor governments, including under Billy Hughes from 1915 to 1916, James Scullin from 1929 to 1932, John Curtin from 1941 to 1945, Ben Chifley from 1945 to 1949, Gough Whitlam from 1972 to 1975, Bob Hawke from 1983 to 1991, Paul Keating from 1991 to 1996, Kevin Rudd from 2007 to 2010 and 2013, Julia Gillard from 2010 to 2013, and Anthony Albanese since 2022.

The Democratic Progressive Party (DPP) is a centre-left Taiwanese nationalist political party in Taiwan. As the dominant party in the Pan-Green Coalition, one of the two main political camps in Taiwan, the DPP is currently the ruling party in Taiwan, leading a minority government that controls the presidency and the central government.

Founded in 1986 by Hsu Hsin-liang, Roger Hsieh and Lin Shui-chuan, a year prior to the end of martial law, the DPP is one of two major parties in Taiwan, the other being the Kuomintang (KMT), a Chinese nationalist party previously ruling the country as a one-party state, and its smaller allies in the Pan-Blue Coalition. It has traditionally been associated with a strong advocacy of human rights, emerging against the authoritarian White Terror that was initiated by the KMT, as well as the promotion of Taiwanese nationalism and identity. Lai Ching-te is the current chairperson of the DPP from 2023, who also serves as the incumbent President and is the third member of the DPP to hold the presidency; he succeeded fellow DPP member Tsai Ing-wen in May 2024.

The Labour Party, commonly Labour, is one of the two main political parties in the United Kingdom, along with the Conservative Party. It sits on the centre-left of the left–right political spectrum, and has been described as an alliance of social democrats, democratic socialists and trade unionists. It has been the governing party since the 2024 general election. Keir Starmer has been Leader of the Labour Party since 2020 and Prime Minister of the United Kingdom since 2024. There have been twelve Labour governments and seven Labour prime ministers.

The Labour Party was founded in 1900, having emerged from the trade union movement and socialist parties of the 19th century. It was electorally weak before the First World War, but in the early 1920s overtook the Liberal Party to become the main opposition to the Conservative Party, and briefly formed a minority government under Ramsay MacDonald in 1924. In 1929 Labour for the first time became the largest party in the House of Commons, with 287 seats, but fell short of a majority, forming another minority government. In 1931, in response to the Great Depression, MacDonald formed a new government with Conservative and Liberal support, which led to his expulsion from the party. Labour was soundly defeated by his coalition in 1931, winning only 52 seats, but began to recover in 1935 with 154 seats.

The German Democratic Party (Deutsche Demokratische Partei, DDP) was a liberal political party in the Weimar Republic, considered centrist or centre-left. Along with the right-liberal German People's Party (Deutsche Volkspartei, DVP), it represented political liberalism in Germany between 1918 and 1933. It was formed in 1918 from the Progressive People's Party and the liberal wing of the National Liberal Party, both of which had been active in the German Empire.

After the formation of the first German state to be constituted along pluralist-democratic lines, the DDP took part as a member of varying coalitions in almost all Weimar Republic cabinets from 1919 to 1932. Before the Reichstag elections of 1930, it united with the Volksnationale Reichsvereinigung, which was part of the national liberal Young German Order (Jungdeutscher Orden). From that point on the party called itself the German State Party (Deutsche Staatspartei, DStP) and retained the name even after the Reich Association left the party. Because of the connection to the Reich Association, members of the left wing of the DDP broke away from the party and toward the end of the Republic founded the Radical Democratic Party, which was unsuccessful in parliament. Others joined the Social Democratic Party of Germany (SPD).

The Coalition of the Radical Left – Progressive Alliance (Greek: Συνασπισμός Ριζοσπαστικής Αριστεράς – Προοδευτική Συμμαχία, romanized: Synaspismós Rizospastikís Aristerás – Proodeftikí Simachía), best known by the syllabic abbreviation SYRIZA (/ˈsɪrɪzə/ SIH-rih-zə; Greek: ΣΥΡΙΖΑ [ˈsiriza]; a pun on the Greek adverb σύρριζα, meaning "from the roots" or "radically"), is a centre-left and former left-wing political party in Greece. It was founded in 2004 as a political coalition of left-wing and radical left parties, and registered as a political party in 2012.

A democratic socialist, progressive party, Syriza holds a pro-European stance. Syriza also advocates for alter-globalisation, LGBT rights, and secularism. In the past, SYRIZA was described as a typical left-wing populist party, but this was disputed after its government term and its recent opposition.

The Social Democratic Party of Austria (German: Sozialdemokratische Partei Österreichs [soˈtsi̯aːldemoˌkraːtɪʃɛ parˌtaɪ ˈøːstɐraɪçs], SPÖ) is a social democratic political party in Austria. Founded in 1889 as the Social Democratic Workers' Party of Austria (German: Sozialdemokratische Arbeiterpartei Österreichs, SDAPÖ) and later known as the Socialist Party of Austria (German: Sozialistische Partei Österreichs) from 1945 until 1991, the party is the oldest extant political party in Austria. Along with the Austrian People's Party (ÖVP), it is one of the country's two traditional major parties. It is positioned on the centre-left on the political spectrum.

Since June 2023, the party has been led by Andreas Babler. It is currently the third largest of five parties in the National Council, having won 41 of 183 seats and 21.1% of the popular vote in the 2024 Austrian legislative election. It holds seats in the legislatures of all nine states; of these, it is the largest party in three (Burgenland, Carinthia, and Vienna.) The SPÖ is supportive of Austria's membership in the European Union, and it is a member of the Progressive Alliance and Party of European Socialists. It sits with the Progressive Alliance of Socialists and Democrats in the European Parliament; of Austria's 19 MEPs, five are members of the SPÖ. The party has close ties to the Austrian Trade Union Federation (ÖGB) and the Austrian Chamber of Labour (AK).

The Italian Republican Party (Italian: Partito Repubblicano Italiano, PRI) is a political party in Italy established in 1895, which makes it the oldest political party still active in the country. The PRI identifies with 19th-century classical radicalism, as well as Mazzinianism, and its modern incarnation is associated with liberalism, social liberalism, and centrism. The PRI has old roots and a long history that began with a left-wing position, being the heir of the Historical Far Left and claiming descent from the political thought of Giuseppe Mazzini and Giuseppe Garibaldi. With the rise of the Italian Communist Party and the Italian Socialist Party (PSI) to its left, it was associated with centre-left politics. The early PRI was also known for its anti-clerical, anti-monarchist, republican, and later anti-fascist stances. While maintaining those traits, during the second half of the 20th century the party moved towards the centre on the left–right political spectrum, becoming increasingly economically liberal.

After 1949, the PRI was a member of the pro-NATO alliance formed by Christian Democracy (DC), the Italian Democratic Socialist Party, and the Italian Liberal Party (PLI), enabling it to participate in most governments of the 1950s, a period later known as Centrism. In 1963, the party helped bring together DC and PSI in Italy's first centre-left government, the Organic centre-left. Although small in terms of voter support, the PRI was influential thanks to leaders like Eugenio Chiesa, Giovanni Conti, Cipriano Facchinetti, Randolfo Pacciardi, Oronzo Reale, Ugo La Malfa, Bruno Visentini, Oddo Biasini and Giovanni Spadolini. The latter served as Prime Minister of Italy in 1981–1982, the first non Christian Democrat since 1945. From 1976 to 2010, the PRI was a member of the European Liberal Democrat and Reform Party (ELDR), along with the PLI, and the two parties usually ran together in European Parliament elections. After joining the centrist Segni Pact in 1994, the PRI was part of the centre-left coalition from 1996 to 2006, and then of the centre-right coalition from 2008 to 2013 (its leader Giorgio La Malfa was Minister for European Affairs from 2005 to 2006). Afterwards, it ran alone until joining the centrist Action – Italia Viva in 2022.

The Socialist Party (French: Parti socialiste [paʁti sɔsjalist], PS) is a centre-left to left-wing political party in France. It holds social democratic and pro-European views. The PS was for decades the largest party of the "French Left" and used to be one of the two major political parties under the Fifth Republic, along with the Rally for the Republic in the late 20th century, and with the Union for a Popular Movement in the early 2000s. It is currently led by First Secretary Olivier Faure. The PS is a member of the Party of European Socialists, Progressive Alliance and Socialist International.

The PS was founded in 1969 from a merger of the French Section of the Workers' International (SFIO), the Convention of Republican Institutions led by François Mitterrand, and other groups. In the 1970s, the PS surpassed the Communist Party's share of the left-wing vote. It first won power in 1981, when Mitterrand was elected president. The PS achieved a governing majority in the National Assembly from 1981 to 1986, and again from 1988 to 1993. PS leader Lionel Jospin lost his bid to succeed Mitterrand as president in 1995 to conservative Jacques Chirac, but he served as prime minister in a cohabitation government from 1997 to 2002, when he was again defeated by Chirac in the presidential election.