“How Politicians Polarize offers a path-breaking shift in our understanding of representation. It introduces negative representation: when elites focus on opposing the other party rather than advancing policy on behalf of their constituents. Costa’s wide-ranging examination reveals how this pernicious practice stems, not from voters’ preferences, but rather from the media ecosystem, non-competitive elections, progressively ambitious politicians, and partisan misperceptions. Costa offers remarkable insight in explaining that a ‘way out’ would be privileging voters’ desires over perceived systemic incentives.”

James N. Druckman | coeditor of "Partisan Hostility and American Democracy"

“How Politicians Polarize reveals a divide between what politicians do and what people truly want. While Americans themselves reject animosity, Costa shows the process by which politicians are nevertheless rewarded for negative attacks. Her multi-method account offers both assurance that Americans disdain this 'othering' but also a dark warning for how negative representation becomes a dominant strain within US politics.”

Samara Klar | coauthor of "Independent Politics"