This paper reviews current theory and research that indicates that attitudes held with strong moral conviction (‘moral mandates’) represent something psychologically distinct from other constructs (e.g., attitude strength, partisanship, or religiosity), and that variance in moral conviction has important social and political consequences, such as increased intolerance of attitudinally dissimilar others, difficulties in conflict resolution, increased political participation, willingness to accept violent means to achieve preferred ends, strong ties to positive and negative emotions, and inoculation against the usual pressures to obey authorities, obey the law, or to conform to majority group influence. The normative implications of these findings are both reassuring (moral convictions can protect against obedience to potentially malevolent authorities) and terrifying (moral convictions are associated with rejection of the rule of law, and can provide a motivational foundation for violent protest and acts of terrorism). Implications and directions for future research are discussed.