Key facts
- Progressive Netherlands, formed by the merger of Dutch GreenLeft and Labour parties, voted to join the Party of European Socialists.
- 65% of Progressive Netherlands members backed joining the PES over the European Green Party.
- An advisory committee recommended joining the PES, citing greater influence at the EU level.
- The PES has prime ministers and European Commissioners, while the Greens have fewer such positions.
- The party's eight MEPs are likely to remain in their current parliamentary groups (four in Socialists and Democrats, four in Greens/European Free Alliance).
- The choice of European party affects EU funding distribution based on MEP share.
The largest opposition party in the Netherlands, Progressive Netherlands (PRO), has opted to join the Party of European Socialists (PES) rather than the European Green Party, according to results announced Friday, September 25, 2026. PRO was formed earlier this year through the merger of the Dutch GreenLeft (GroenLinks) and Labour (PvdA) parties.
In an internal vote, 65% of PRO members supported aligning with the PES. An advisory committee had previously recommended this path, arguing that membership in the PES would grant the party greater influence within the European Union due to the group's representation among prime ministers, European Council members, and European Commissioners. The committee noted that the Greens have fewer such high-level positions.
PRO leader Jesse Klaver has previously attended PES meetings, including one in June alongside Spanish Prime Minister Pedro Sánchez and Danish Prime Minister Mette Frederiksen.
The party's eight Members of the European Parliament (MEPs) are expected to remain in their current parliamentary groups, with four likely staying with the Socialists and Democrats and four with the Greens/European Free Alliance. However, the choice of European party affiliation will impact the allocation of EU funding, which is distributed based on a party's share of MEPs. PRO indicated that they might review the MEP arrangement before the next European Parliament election in 2029, with one option being for the former GroenLinks MEPs to technically leave PRO to be counted separately for funding purposes.