Baker A, Ames B, Sokhey AE, Renno LR.  JOURNAL OF POLITICS. 78 (1) (January 01, 2016): 197-213.

Abstract:
What happens to partisanship when a party undergoes rapid and visible elite-led changes that dilute its traditional brand? We address scholarly debates on the stability of mass partisanship by analyzing the consequences of the major brand change (marked by policy moderation and scandal) experienced by the leftist Brazilian Workers Party (PT) between 2002 and 2006. Analyzing a survey panel with interviews spanning this period, we find that many Brazilian citizens alternated between petismo and independence but rarely crossed party lines. They switched, we demonstrate, in response to political events. While the PT’s brand dilution drove away some traditional petistas, we observe two other dynamics: the rise of a new brand associated with the successful incumbent president (Lula) attracted new adherents, and amid this instability, a core of petistas stood by their party. Our findings suggest that scholarship on partisanship has established a false dichotomy between stability and instability.