At a time when the United States faces unprecedented challenges at home and abroad, public schools must do far more to prepare young people to be engaged, ethical advocates of "liberty and justice for all." This article explores what makes some people behave ethically--even at the risk of their own lives--and asserts that developing moral habits of the heart is the central mission of schools. It describes "schools of conscience" that support students in their search for meaning while teaching them the civic principles and virtues necessary for sustaining the common good in a democracy.