Moral disagreement across politics revolves around the key question, “Who is a victim?” Twelve studies explain moral conflict with assumptions of vulnerability (AoVs): liberals and conservatives disagree about who is especially vulnerable to victimization, harm, and mistreatment. AoVs predict moral judgments, implicit attitudes, and charitable behavior—and explain the link between ideology and moral judgment (usually better than moral foundations). Four clusters of targets—the Environment, the Othered, the Powerful, and the Divine—explain many political debates, from immigration and policing to religion and racism. In general, liberals see vulnerability as group-based, dividing the moral world into groups of vulnerable victims and invulnerable oppressors. Conservatives downplay group-based differences, seeing vulnerability as more individual and evenly distributed. AoVs can be experimentally manipulated and causally impact moral evaluations. These results support a universal harm-based moral mind (Theory of Dyadic Morality): moral disagreement reflects different understandings of harm, not different foundations.