Rule of law backsliding across regime types: a comparative analysis of the role of party cohesion in shaping backsliding dynamics

Abstract The rule of law around the world has increasingly been eroded by elected governments seeking to expand their power. A traditional mechanism against rule of law backsliding is the horizontal and vertical separation of powers, as it creates veto points across the political system. Yet, endogenous erosion of the rule of law is progressing in consolidated democracies across regime types and despite institutional and contextual variation. We argue that this warrants a broadening of perspective beyond static formal institutions and encompassing cases on both sides of the ‘transatlantic divide.’ In order to increase our understanding of the functioning, effectiveness, and limits of these mechanisms, we systematically compare the backsliding dynamics at play across six exploratory cases in Europe and the Americas. We argue that the effectiveness of veto players critically depends on partisan cohesion around rule of law backsliding. Using the cases of Brazil, Hungary, Poland, Romania, the U.K., and the U.S., we illustrate how leaders commanding cohesive national(ized) parties are able to subvert institutional checks as well as underlying norms supporting the rule of law and liberal-democratic principles like judicial independence and legitimate political opposition and dissent across levels of government in the pursuit of their backsliding agenda.