Membership Rise of the Labour Party of Belgium amidst the Decline of the Left in Europe

Against a backdrop of rising populism, declining democracy and increasing authoritarianism, political parties in Europe, regardless of their ideological leanings, are experiencing a continuous erosion of their militant bases. This phenomenon is affecting the so-called “traditional” parties, including the social-democratic left, particularly hard.
Belgium's Socialist Party is a striking example. Formerly a mass party, its membership has been falling for years. This loss of membership was accompanied by a significant electoral defeat in the June 2024 elections, which led to a reduction in its representation at all levels of power (regional, federal, European). This twofold phenomenon testifies to this party's difficulty in maintaining a strong societal anchoring.
In this context, the Labor Party of Belgium (PTB-PVDA), a radical left party of Maoist origin founded in 1979, is an exception. Its membership has risen from 1,254 in 2000 to 2,890 in 2008, reaching 20,276 in 2019 and 24,000 in 2022. This strong growth has been accompanied by a steady electoral advance over the last ten years. Although little studied, the PTB-PVDA, which defines itself as the “authentic left”, provides a rare and valuable case study for understanding the driving forces behind party membership, at a time when it is in decline.
This research explores how the PTB-PVDA (re)constructs its activism on a daily basis. How can we explain its success in recruiting and retaining activists while other parties in Europe are struggling to mobilize ?
To answer this question, the research is based on qualitative methods, including the analysis of a corpus of party documents (archives, daily magazine, statutes, Congress documents, leaders' books), interviews with members to understand their motivations for joining and staying in the party, and an extended ethnographic immersion, begun 7 months ago and still ongoing, in a local PTB-PVDA group. This approach enables us to grasp the inner workings of the party, its recruitment strategies and members' modes of action, offering a “bottom-up” perspective.
Beyond the Belgian case, this research proposes to discuss the state of the left and the radical left in Europe today, and will address avenues for a potential “way out of the crisis”.