The issue that provoked the split from KEN(ml) was an intense debate on the role of intellectuals in the class struggle.

The founders of KPN/ML, with Daan Monjé in a prominent role, belonged to the proletarian wing of the KEN(ml), who did not want an organisation dominated by students and intellectuals.

Even in its early years, while adhering to Maoist principles such as organising the masses, the SP was very critical of the Chinese Communist Party, condemning its support for UNITA in Angola with the brochure "Antwoord aan de dikhuiden van de KEN" ('Answer to the thick skins of the KEN').

The SP had its own General Practitioners' offices, provided advice to citizens and set up local action groups.

In the 1998 general election, the party was rewarded for its opposition to the purple government of the first Kok cabinet and more than doubled its seats to five.

However, these gains failed to materialise as many potential SP voters chose to cast strategic votes for the Labour Party which stood a good chance of winning the elections.

As a result of the provincial elections, the SP has increased its representatives in the Senate of the Netherlands (upper house) to 11 from the 4 it had previously.

The party's popularity rose after the election, with polls throughout 2012 indicating it could challenge the ruling VVD with a seat count reaching into the 30s.

The SP's popularity peaked in early August, a month before the election, with polls from Peil, Ipsos, and TNS NIPO indicating it would become the largest party with a result as high as 37 seats.

[29] The party labels itself as socialist,[30] and in its manifesto of principles, it calls for a society where human dignity, equality and solidarity are most important.

[15] The party program is heavily focused on Dutch blue collar workers, recalling a 'historical homeland' of Dutch workers that was destroyed by privatisation, deregulation and neoliberalism; in the same vein, the party is critical of the EU, calling its policies 'false internationalism' and accusing it of being in the service of big corporations and neoliberalism.

[35] Apart from campaigning on restricting immigration, the SP opposes climate change measures that it considers unfair or disadvantageous to the working class.

It also strongly opposes a "European superstate" and demands the return of the Dutch national currency, the Dutch guilder; in addition, the party supports border controls within the EU, and advocates introducing a work permit requirement for people entering the Netherlands from other EU countries.

Given the party's social stances, its voter base consists of low-income and working-class Catholics of the Southern Netherlands, as well as trade union members.

[36] It combines its social stances with an anti-neoliberal rhetoric, calling for the end of the elite's "pillage of the state, deception, and flogging off its people to a cabal of foreign capitalists".

After its disastrous election result in 2002, the PvdA, now back in opposition, did co-operate with the SP against some of the policies of the centre-right Balkenende government and their relationship improved significantly.

The SP is also part of several municipal executives (College van burgemeester en wethouders), notably in Amsterdam and Utrecht.

The congress decides on the order of the candidates for national and European elections and it has a final say over the party program.

[40] An example more of nationwide nature is the movement for a National Healthcare Fund (Dutch: Nationaal ZorgFonds).

The expensive advertising annually organised by healthcare insurance companies in order to attract new customers is a big example.

The SP publishes the magazine the Tribune monthly[42] which was also the name of a historical Communist Party of the Netherlands newspaper.

The relationship between Rood and the SP became rocky in 2020 due to the youth wing taking a more radical approach to politics.