The two faces of Janus: National Brazilian party organizations and local politics

Even operating under the same national institutional incentives and considering eventual electoral advantages (Tavits, 2013; Samuels & Zucco, 2014), why do not Brazilian political parties homogenize their municipal-level party branches by "contagion effect" across the territory (Duverger, 1958)? Despite the high party fragmentation in the House of Representatives (23 political parties in the 56th legislature), most of 5570 Brazilian municipalities have only 2 to 3 local party branches. Considering the territorial network of party branch offices between 2012 and 2020 (three local elections), this article argues that the party-building does not reflect only federal incentives but also follows the local dynamics (Geser, 1999; Clark, 2004), particularly the mayors' elections. Based on panel pooled analysis, we find that the majoritarian electoral system for electing mayors is associated with the less local presence of political parties, mainly because the single-member plurality districts demand fewer local party organizations (Harmel & Janda, 1982). Although building a strong party organization can help with recognition, expectations of viability, and differentiation from the other entrants (Cox, 1997; Tavits, 2013), the majoritarian electoral system limits the investments of national parties in local party organizations beyond the duvergerian equilibrium (M+1). The argument rests on the assumption that parties avoid investing scarce resources in a local organization in municipalities with no prospect of winning the mayoral elections (Duverger, 1958; Cox, 1997). Furthermore, the polity size and socioeconomic context of the localities are relevant: on the one hand, larger municipalities (electorate size), which have more financial (GDP per capita) and civil society density (NGOs, unions, etc), stimulate the formation of local party organizations (Dahl & Tufte 1974; Geser, 1999; Samuels & Zucco, 2014). On the other hand, in the case of micro-municipalities (less than five thousand habitants), where more personalistic political relationships predominate, the benefits of consolidating the local party organizations are limited (Dahl & Tufte 1974; Geser, 1999). In sum, this paper argues that the organizational network of political parties is influenced by local institutions (plurality electoral system) and the socioeconomic salience of municipalities (Geser, 1999).