Americans have long been prone to conflict over moral values and their appropriate role in society. As a result, moral issues frequently play a critical and divisive role in U.S. politics. However, the process by which individuals apply their moral judgments to politics is still poorly understood. Moral judgments and legal positions are distinct, as evidenced by an overlooked but consistent gap in opinion over time on the morality and legality of various moral issues. I contend that one's perceived level of moral knowledge, which I call moral confidence, accounts for this variation in respondents' willingness to translate their moral beliefs into legal positions. To test this theory, I leverage preexisting and original survey data to demonstrate the persistence of a morality-legality gap in opinion across the issues of abortion, homosexuality, capital punishment, and physician-assisted suicide. Furthermore, I demonstrate that moral confidence explains this gap; those with lower moral confidence are more likely to hold incongruous moral and legal opinions. Moreover, many respondents overestimate their moral knowledge, which leads them to take more extreme political positions on moral issues. Indeed, experimental evidence suggests that respondents moderate their positions on moral issues when prompted to actually explain their moral beliefs. Thus, how much we know—or think we know—about right and wrong determines how forcefully we apply our moral beliefs to politics.