We examine the rise and mobilizational dynamics of social democracy, employing data reported by the Swedish authorities on the distribution of voting eligibility, turnout and partisan vote in local elections during the 1910s at a high level of disaggregation (by narrow income segments and administrative units). In line with the existing literature, we show that electoral socialism depended on both the extension of the suffrage to its ‘natural’ electorate, that is, the urban working class, and the organizational capacity of trade unions and other civic associations. In addition, we show that socialist support was not uniform within the working class – even for a highly homogeneous society. Instead, the social-democratic vote was initially stronger among low- to middle-income workers, only expanding to poor voters later in time. We complement our local data with an interwar panel analysis of socialist vote and post-war survey data.

Party leaders continue to be crucial players in politics. The theories of personalization and presidentialization of party politics reflect the centrality of leaders’ roles. Little attention has been paid to the effects of leaders on the formation and development of newly emerged parties. This article aims to fill that gap by analyzing the effect of leaders on the formation, intra-party cohesion, and membership organization of three newly emerged Romanian parties between 2015 and 2019. The qualitative analysis uses content from primary (party documents and elite discourses) and secondary sources (media reports). The findings indicate that the leaders’ approaches towards party formation and organization differ substantially across the examined parties and explain their cohesion and electoral appeal.

In this paper, we study how political parties react to democratic transitions. We find that the structure of legislators’ social networks plays a critical role in shaping their political interactions during the transition period, and consequently, the post-transition party systems that emerge. We focus on the Korean case, where the incumbent authoritarian party merged with one of its pro-democracy opponents to create a powerful and enduring conservative party under democratic rule. Using a novel individual-level dataset on all legislative members during the transition, we find that the merger was facilitated by dense social networks linking members of the merged parties, which increased trust across the parties and reduced the difficulty of a merger. Conversely, we find that the paucity of ties linking pro-democracy parties hindered their long-term cooperation, despite their shared ideologies and policy goals. The study complements existing theories by providing a network-based explanation for the weakly institutionalized political party system that has characterized Korean politics since democratization.