According to Silvan Tomkins' polarity theory, ideological thought is universally structured by a clash between two opposing worldviews. On the left, a humanistic worldview seeks to uphold the intrinsic value of the person; on the right, a normative worldview holds that human worth is contingent upon conformity to rules. In this article, we situate humanism and normativism within the context of contemporary models of political ideology as a function of motivated social cognition, beliefs about the social world, and personality traits. In four studies conducted in the U.S. and Sweden, normativism was robustly associated with rightist (or conservative) self-placement; conservative issue preferences; resistance to change and acceptance of inequality; right-wing authoritarianism and social dominance orientation; system justification and its underlying epistemic and existential motives to reduce uncertainty and threat; and a lack of openness, emotionality, and honesty-humility. Humanism exhibited the opposite relations to most of these constructs, but it was largely unrelated to epistemic and existential needs. Humanism was strongly associated with preferences for equality, openness to change, and low levels of authoritarianism, social dominance, and general and economic system justification. We conclude that polarity theory possesses considerable potential to explain how conflicts between worldviews shape contemporary politics.