Legislative Constraints on Executive Unilateralism in Separation of Powers Systems

Can legislatures effectively check unilateral executive power? One prominent and counterintuitive finding in previous work is that executives pursue unilateralism less often under divided government. While executives see greater potential policy gains through unilateral action during divided government, we argue that their likelihood of acting unilaterally depends on an opposed legislature's ability to retaliate. When polarization is high and majorities are marginal, executives are freer to act unilaterally given the difficulties legislatures have in statutorily responding. Unilateralism is also more likely when facing opposition if legislatures lack nonstatutory means of punishment, such as regulatory review. In the largest analysis of gubernatorial executive unilateralism to date, we use a new data set of 24,232 executive orders in the 50 American states between 1993 and 2013 to evaluate this argument and find strong support for its predictions. These results provide insights into how legislative policymaking capacity can influence the functioning of separation of powers systems.