Pairs of states, which are more similar to each other in their regime characteristics, have been found to be interconnected through diplomatic ties, international organizations, and other international relations more frequently. This holds for democracies as well as for rather authoritarian regimes. This finding has been frequently addressed in quantitative studies on the diffusion of democracy.
This paper broadens this perspective and focuses on the diffusion of regime characteristics in general, allowing for democratic as well as authoritarian diffusion. A social network perspective is adopted, which has only recently been introduced into Comparative Politics and International Relations. A stochastic actor-oriented model for the simulation of network evolution (SIENA) is applied for testing two competing explanations: influence and selection.
According to the first explanation for the observation of frequently connected states with similar political regimes (influence), the diffusion of norms and institutional arrangements through international networks fosters individual states changing their political regime and becoming more democratic or more authoritarian. If this argument holds, nondemocratic or less liberal states that are well connected to democracies or more liberal states should be more prone to political liberalization. A second explanation postulates a causal relationship in the opposite direction (selection): States with similar regime characteristics are theorized to be more likely to connect with each other over time and establish bilateral diplomatic relations, for example. Only if the first of these two explanations is supported by empirical evidence, the importance of diffusion is strengthened.
