This chapter elaborates the argument developed inby empirically evaluating existing theories of the tax burden and using that analysis to construct an explanation of variance among the case study countries. While most theories are unconvincing, three variables from the literature do resonate with the cases: non-tax natural resource revenues, certain distinctive features of the Brazilian and Chilean constitutions and, most crucially, an expanded version of the power resource perspective, which suggests that the tax burden reflects the balance of power been statist and anti-statist forces. The shortcoming of this argument is that it does not explain cross-national differences in this power balance. Hence, the chapter develops an account, drawing on path dependence theory, tracing these differences to the occurrence or not of reform waves that threatened private property. Where such waves occurred, in Chile and Mexico, they impeded future taxation by prompting the formation of enduring anti-statist blocs anchored by peak business associations and rightist parties. In Argentina and Brazil, in contrast, such waves did not occur and anti-statism remained a less powerful force.