They had left the PvdA over the military intervention against the Indonesian independence movement and the Labour party's support for NATO.

[citation needed] These politically homeless individuals were a diverse group: progressive Christians, orthodox Marxists, Trotskyists, liberal pacifists and some anarchists.

The first year was devoted to the organisation of the party and the preparation for the elections which were expected to be in 1960.

The founders were joined by members of the Socialist Union, a group which had split unsuccessfully from the PvdA in 1950.

In the early years, the party became known for its parliamentary and extra-parliamentary opposition against the rising Cold War, and especially the placement of nuclear weapons.

Extra-parliamentary action against colonialism also became more important; the party supported New Guinean and Algerian independence.

This success can be attributed to several developments: the rising opposition to the Cold War, the party's appeal to the developing students' movement and especially the anarchist Provo movement, for whom the PSP was the only acceptable party, and finally the CPN's internal conflicts – in 1958 three MPs had left the CPN and formed their own parliamentary party, led by Henk Gortzak, called the Bridge Group (Dutch: Brug-groep) and unsuccessfully competed in the 1959 elections.

The monarchy also became an issue as Crown Princess Beatrix would marry Claus von Amsberg in 1966.

In 1972, the party's political leader, Hans Wiebenga (1917–2005) was replaced by the younger Bram van der Lek, who emphasized the environment as an important issue.

As party leader he would embrace extra-parliamentary protest of all kinds of groups: the PSP was involved in the nascent environmental, squatting, women's and students' movements.

In 1974 nearly all of them (except for their leader Meijer) left the party to found what later became the group Socialist Alternative Politics.

Nevertheless, the 1977 elections were disastrous: the party lost all but one seat – this is attributed to the political competition between the social-democratic prime minister Joop den Uyl and his Christian democratic competitor Dries van Agt, which caused many PSP-sympathizers to vote for Den Uyl.

In the early 1980s, the placement of American nuclear weapons became an important political issue.

At the 1984 European Parliament election, the PPR, CPN and PSP formed the Green Progressive Accord that entered with one joint list.

In the elections of 1986 nuclear weapons were no longer an issue: the party was left with only one seat.

Their initiative was supported by an open letter from members of trade unions, environmental movements and the arts which called for one progressive formation left of the PvdA.

[citation needed] The PSP made a considerable mark on GreenLeft, although it has moderated its pacifism and socialism.

MPs Kees Vendrik, Ineke van Gent and Leo Platvoet were active within the party, as was MEP Joost Lagendijk.

In its 1957 manifesto of principles,[3][better source needed] the PSP advocated two major societal renewals: Firstly, a spiritual renewal, which sought to replace a society based on fear, division and power with a society based on trust, unity and justice – this reflected the party's pacifism.

[citation needed] In the 1970s and 1980s, new issues were incorporated into the PSP's ideology: women's liberation, gay rights, and environmentalism.

[citation needed] The PSP advocated a democratic socialist society where government planning and workers' self-management played an important role:[citation needed] The PSP advocated an anti-militarist and socialist foreign policy:[citation needed] On the national level, the party advocated radical democratization of society and protection of civil rights: The PSP wanted to radically feminize society, liberate other oppressed groups and democratize society: This table shows the PSP's results in elections to the House of Representatives (HoR), Senate (S), European Parliament (EP), States-Provincial (SP) and municipalities (M), as well as the party's political leadership: the fractievoorzitter is the chair of the parliamentary party and the lijsttrekker is the party's top candidate in the general election.

The PSP had a provincial stronghold in North Holland, which gave the party more than half of its vote.

The electorate of the PSP fluctuated; the changing appeal of the PvdA and the CPN played a role, as did the events of the Cold War.

The rise of youth movements, like Provo, and the Vietnam war boosted the electorate of the party in the 1960s.

The mass demonstrations against the placement of nuclear weapons boosted the party's support in the early 1980s.

The PSPs youth was organised in the Pacifist Socialist Young Working Groups (Dutch: Pacifistisch Socialistische Jongeren Groepen, PSJG) between 1977 and 1991.

The Rode Draad was published since 1985 it was a magazine for municipal and provincial councillors the PSP, PPR and CPN.

Before the party was founded, the group of politically homeless activists had asked to have an independent candidate on their lists.

In 1971 the PvdA, which had become more leftwing under pressure of a new generation of party members, opened the door to the PSP.