This paper addresses why the common challenges of late development have generated starkly different responses in the global south. More specifically, I analyze what I term the national developmentalist regimes in Mexico, Turkey, Argentina, and Egypt during the middle half of the 20th century. The larger purpose of this paper is to situate Kemalism as part of a broader category of reformist regimes in the developing world and to facilitate its systematic investigation. Whereas nationalist regimes in Mexico and Egypt displayed astonishing durability even during times of economic downturn, Kemalist and Peronist elites failed to establish a stable political order in Turkey and Argentina, respectively. In particular, what accounts for the rapid demise of the Kemalist single-party regime? I attribute this outcome to Mustafa Kemal’s reluctance, given the low-level of intra-elite conflict and limited popular mobilization, to invest in the building of state infrastructural power and ruling party strength at the onset of his regime. Due to the relative weakness of ruling-party and state corporatist institutions, in sharp contract with Mexico and Egypt, the Kemalist elites could only establish a limited political base and thus remained vulnerable to the defection of elites, who could mobilize popular classes against the governing party.