Public sector unions are increasingly becoming the hegemonic contemporary labor actor in terms of membership and militancy in both advanced and emerging economies. However, political economy lacks a unified theoretical approach to study mobilization by state unions. The analysis of public sector union politics has been largely separated by regional (United States vs. Europe vs. Global South) and disciplinary (American politics vs. comparative politics/political sociology) divides. We contend that though both public and private workers belong to the subaltern classes, public sector union politics and mobilization have different foundations than in the private sector. Unlike private unions, state labor mobilization is essentially driven by what we call the “reverse economic cycle” (militancy increases in bad—rather than good—economic times), by the legal enforcement of bargaining rights (which in contrast to the private sector substantially varies across and within democracies), and by the likelihood of a political exchange between labor and the government. Argentine teachers between 2006 and 2019 provide an ideal laboratory to test this argument through a multilevel (i.e., national and subnational), mixed-methods strategy, which includes comparative and statistical assessments.