The received wisdom among scholars and policymakers generally contends that democracy, as opposed to dictatorship, diminishes the risk of large-scale political violence. This study explores its antithesis, and contends that democracy does not necessarily pacify domestic political contention, and that dictatorship yields several political outcomes that are conducive to domestic peace. It does so by treating democracy not primarily as a “level” concept reflecting contemporaneous levels of democracy, but as a “stock” concept that represents the historically accumulated stock of democratic experiences. This “stock of democracy” imperils domestic peace in several ways. By augmenting the coercive capacity of non-state political actors and radicalizing them, and through their effects upon perceptions of political empowerment among ordinary citizens, prior democratic experiences spur the emergence, lethality and mobilization of mass movements of resistance, referred to as "political campaigns”. An extensive authoritarian history, which amounts to a greater “stock of dictatorship”, on the other hand, pacifies the methods of coercion of these political campaigns by eliminating and deradicalizing opposition groups. Furthermore, by deradicalizing allies and opponents of the government, in authoritarian contexts the stock of dictatorship reduces the scope and severity of state-led efforts to repress civil resistance campaigns and violent insurgencies. I estimate these effects by drawing upon several global datasets, and unpack the underlying mechanisms through an empirical focus upon twenty Latin American countries.