Well-financed opposition parties can undercut the territorial advantages of clientelistic machines. In the 2000s, the leftist Workers’ Party (PT) upended the conservative political establishment in Brazil’s populous Northeast region (NE). In contrast to arguments attributing the PT’s electoral progress in the NE to civil society, economic growth, and conditional cash transfers, we argue that the territorial expansion of the PT organization played a central role. A spike in party finances during the early 2000s enabled the PT, for the first time, to establish party offices in Northeastern municipalities from the top down. We draw from underutilized data to show that the PT strategically targeted conservative-dominated municipalities in the NE. This top-down territorial targeting produced considerable gains for party candidates across federal and state races.

Does party organization still matter? Much of the party literature suggests that politicians, who can use substitutes like mass media to win votes, lack incentives to invest in party organization. Yet party organization remains an electoral asset, especially at lower levels of government. Evidence from Brazil’s Workers’ Party (PT) indicates that party elites invest in organization when they prioritize lower-level elections, and that this investment delivers electoral returns. In the mid-2000s, the PT strengthened its support across levels of government in the conservative, clientelistic Northeast. Drawing from underutilized data on party offices, this article shows that organizational expansion contributed substantially to the PT's electoral advances in the Northeast. While President Lula da Silva’s (PT) 2006 electoral spike in the Northeast resulted from expanded conditional cash transfers, the PT’s improvement at lower levels followed from top-down organization-building. The PT national leadership deliberately expanded the party’s local infrastructure to deliver electoral gains.