Recent years have seen a rise of populist political parties with autocratic leanings around the world which has puzzled academics, policy-makers, and lay people alike. In this chapter, we describe how such trends can be partially explained by a cultural fault line that has an evolutionary basis, namely the strength of social norms or tightness–looseness (TL). Tight societies have strong norms and punishments for deviance, while loose societies have weaker norms and a wide range of permissible behaviors. One important determinant of tightness is the degree to which societies experience ecological and social threats. In contexts where there is chronic warfare, disease outbreaks, or resource scarcity, societies need stronger rules and leaders to coordinate to survive. These dynamics, however, are not limited to groups that experience chronic threat. Individuals who perceive threat—whether real or imagined—also show the same patterns. We theorize that autocratic leaders harness the power of threat to gain voter support, and that individuals who fear ecological and social threats desire tighter cultural norms and are especially likely to support autocratic leaders. Data from two election cycles, the 2016 election cycle within the United States and the 2017 election cycle within France, support this prediction. In both contexts, we found that people who felt threatened believed their countries needed to be tightened, and this in turn partially explained their support for autocratic candidates. Implications for research on populism and policy implications are discussed.