Scaling laws of political regime dynamics: stability of democracies and autocracies in the twentieth century

In light of the current rise of authoritarian regimes and the anti-liberal tendencies in some established democracies, understanding the dynamic and statistical properties of political regimes is of critical importance. Despite their relevance, a comprehensive quantitative assessment of these dynamics on a historical scale remains largely unexplored, and the notion that democratization is an irreversible process has gone mostly unchallenged. This study provides a rigorous and quantitative analysis of political regimes worldwide by examining changes in freedoms of expression, association and electoral quality throughout the twentieth century. Utilizing the multidimensional V-Dem dataset, which covers over 170 countries across more than a century, alongside tools from statistical physics, we demonstrate that historical political regime dynamics follow a scaling law, which is a hallmark of diffusion. We identify three distinct dynamical regimes in the data: super-diffusive behaviour in destabilizing autocracies, random-walk dynamics in hybrid regimes and sub-diffusive behaviour in democracies and stable autocracies. Using these results, we also offer a novel perspective on the propensity of civil conflict.