Presidential Signing Statements and Separation of Powers Politics

Research on presidential policymaking tends to mostly focus on the ways in which congressional actors shape executive decisions. Yet, the judiciary and bureaucracy are crucial in sustaining presidents' direct actions. Accordingly, this paper considers how both influence the use of signing statements through the president's desire to impact the interpretation and implementation of the law. By empirically testing Thrower's (2019) formal model, I find that presidents are more likely to issue constitutional signing statements when ideologically aligned with both the Supreme Court and Congress, i.e. when opposition from these two branches of government is less imminent. Building off theories of delegation, I also find that presidents are more likely to issue agency signing statements when bureaucratic drift is the most likely — that is, when the responsible agency is ideologically distant, independent, and granted sufficient discretion. Overall, this study demonstrates that both inter- and intra-branch dynamics are important for understanding presidential policymaking.