Pre-Analysis Plan: When leaders trump party? Disentangling leader cues from partisanship in mass polarization

Do the leader’s stances on issues carry more weight in persuading voters than the traditional positions of the party? And who is more likely to rally behind the leader over the party itself? In this pre-analysis plan, we define a cue as a message utilized by individuals to inform their decision-making process (Bullock 2020). We study the Brazilian context, specifically, because it presents an ideal case for addressing the problem of leader and party cues being observationally equivalent in a two-party system. That is, well-known politicians may always come attached with a party label, and politicians rarely change across the two parties. In Brazil, multiple politicians have prominence outside any party brand and have been elected and re-elect over the years by multiple party brands. We categorize these politicians as unbranded leaders, while those closely associated with a party are categorized as branded leaders. Therefore, this political context presents an optimal empirical setting for testing the effects of leaders and party cues independently, free from any form of deception.

While party cues are indicative of polarization due to their reflection of partisanship, they also convey information about ideological stances (e.g., Barber & Pope 2019), policy agreement (e.g., Dias & Lelkes 2021), and leader affiliations within the party’s brand, which have been largely overlooked in the literature. We propose an experimental study in which we formulate our leader affiliations hypotheses based on polarizing and persuading effects. For example, Nicholson (2012) finds leader cues as polarizing information capable of swaying voters’ opinions in the opposite direction for out-party members (i.e., polarization effect), more significantly than in-party member endorsement with their own position (i.e., persuasion effect).

In 2022, President Lula’s electoral triumph for a third government raises a fundamental question: Is it leader cues, referred to as lulismo, more influential than party cues, specifically the petismo? Singer (2012) characterizes lulismo as a movement without ideological stances, rooted in economic growth and retrospective evaluations of the economy. Conversely, Samuels and Zucco (2014) conclude that petismo is more enduring than lulismo but fail to precisely define which of these cues polarizes or persuades voters’ opinion more effectively. The new electoral success of President Lula implies that voters tend to align with the leader, while simultaneously polarizing along party lines. That is, while party cues may polarize voters’ opinions, leader cues tend to distinguish themselves by persuading voters.