This third chapter reviews neuropolitics, which documents self-regulation, conflict monitoring, emotional processing, and related physiological and anatomical individual differences predictive of political predilections [Kanai et al., Current Biology, 21(8), 677–680 (2011)]. For instance, augmented anterior cingulate cortical volume, along with amygdala, insula, and entorhinal cortical regions, are among the brain structures covarying with political ideology. Direct measures of brain differences, such as the increased insula size among Democrats, are better predictors of voting behavior than parental party affiliation and related sociodemographic data [Schreiber et al., PLoS One, 8(2), e52970 (2013)]. As another example, take the right entorhinal cortex, a part of the hippocampus active in time-perception and memory that shows increased volume among conservatives (Haas, 2016). This chapter also considers the smaller and newer body of neuroendocrine research as it relates to political affiliation. For example, McDermott et al. [American Journal of Political Science, 58(4), 997–1005 (2014)] found that people could detect olfactory cues enabling them to assortatively mate based on political ideology. These anatomical and physiological differences predict perceptual and attitudinal differences that, in turn, predict political and ideological differences. As emphasized in this third chapter, neurobiological underpinnings of political differences expressed in modern nation-states extend from more fundamental and preexisting individual differences expressed throughout prehistory and ancient history. The neurobiological hardware we bring to the voting booth began evolving before humans were human, and continued evolving throughout prehistory into historical times—a point integral to producing a convincing evolutionary explanation.