What parties are setting the party organisation model in Spain? Assessing organisational convergence between mainstream and new parties in Spain

In the past decades, we have seen the transformation of European party systems with the emergence and success of non-mainstream parties such as green parties, left anti-austerity parties and far-right parties. These parties showed an interest in a new set of issues, which were less dominant in traditional parties, and a change in party organisations that reflected their ideas. For instance, in the case of green parties, this led to a higher inclusion of participatory mechanisms within party organisations (Poguntke, 1993). However, this has not necessarily been the case in more traditional parties such as mainstream parties. As Katz and Mair (2018) discuss, mainstream parties are evolving towards a predominance of the party in public office. Are new parties and mainstream parties’ organisations developing differently? Could there be a contagion effect between them? And if so, in which direction? While mainstream parties have often accommodated some of the issues promoted by new parties (e.g., climate change), it is less clear if this has also been the case from an organisational perspective. More research is needed, thus, to determine if mainstream parties have adopted some of the organisational traits of new parties or vice versa. Recent research on party organisation points towards the lack of convergence in party organisations. While they might identify common organisational patterns among parties competing in the same institutional context, they also point out how organisational differences go beyond party types (e.g., party organisation models or party families) (see Pizzimenti et al. 2022; Scarrow, Webb, and Poguntke 2017). In that sense, previous research shows a model of party organisation applicable to all parties has proven non-existent. These studies point towards a selective contagion effect among parties competing in the same political environment (Webb, Poguntke and Scarrow, 2017). It implies parties follow strategic motivations when implementing similar organisational structures or decisions. As such, some elements of new parties might have spread to mainstream party organisations if they had incentives for it and vice versa. Following a case study approach of the Spanish case, this paper aims to assess if mainstream and new parties organisations are converging, the direction of this convergence and identify its main drivers. To do so, I will qualitatively analyse the organisational evolution of PSOE, PP, IU, Podemos, Ciudadanos, and VOX from 2014 to 2022, building on party statutes, media reports and additional party documents.