Boldt, Damian. "Are Democracies Inherently Peaceful? Re-Evaluating the Monadic Democratic Peace with Causal Inference." Working Paper (most recent draft September 2021).

Abstract: Although some scholars have declared there to be a consensus that there is no such thing as a monadic democratic peace, multiple theories of interstate conflict expect there to be one. Furthermore, the existing empirical evidence is inconclusive and suffers the limitations endemic with observational research designs. I revisit this ongoing debate and empirically test for the existence of a monadic democratic peace. First, I apply a TSCS matching design and a difference-in-differences estimator developed by Imai, Kim, and Wang (2020). This estimator allows me to causally identify treatment effects, making my estimates the most credible causal estimates to date. I also employ a series of specialized random effects models that allow me to parsimoniously distinguish between within-unit and across-unit effects. All of my analyses lead me to the same conclusion --- democracies are just as likely as autocracies to initiate interstate conflict.