Few regions of the world have been subject to deeper US political, military, and economic penetration than the Middle East and Latin America. Accordingly, scholars of both regions identify US intervention as a central cause of authoritarian durability, arguing that authoritarian clients propagated pro-American foreign policies and suppressed domestic opposition in exchange for US interventions that supported their own longevity. In both regions, the US supported robust coercive apparatuses, provided large-scale economic aid and public goods, and even assumed control over specific government functions. Despite these similarities, few comparisons exist between the contemporary Middle East and historical antecedents in Latin America. This paper supports the belief that a cross-regional comparison is useful for revisiting the intervention/authoritarianism hypothesis, as well as for understanding the relative durability of Middle Eastern authoritarianism. Thirty-five years after the beginning of the "Third Wave," it is evident that American intervention was not a sufficient condition for authoritarian durability in Latin America, which experienced both significant fluctuation in authoritarian rulers and region-wide democratization amidst an environment of sustained US political, economic, and military interference. This realization leads us to question the causal impact of American intervention in the Middle East, and to seek out other factors that might explain the degree of authoritarian durability across both regions. Drawing upon a series of mini-case studies, including Nicaragua, Chile, Brazil, Iran, Jordan, and Egypt, this paper explains the relative durability of authoritarianism in the Middle East relative to Latin America. It argues that the effect of US interventions on authoritarianism is strongly conditioned by several other factors, particularly (1) the availability of other sources of external rent, including oil revenues and alternative sources of foreign aid; and (2) the organization and composition of the labor force. With few exceptions, Latin American countries lacked access to large-scale external rents, which allowed for capitalist development and the formation of organized labor movements that became the most vocal opponents to American-backed authoritarian regimes. By contrast, Middle Eastern countries had access to a variety of external rents, which were funneled through the state apparatus to society. These rentier economies did not undergo capitalist development, were concentrated largely in services, and imported, corporatized, and/or excluded women from the labor force, rendering labor unmobilized, fragmented, and weak.