The principle of legal paternalism allows that it is a good reason for a law that the adult person affected by the law is herself benefited or at least prevented from harming herself, often despite her occurrent desires and choices. Laws prohibiting the sale, purchase, or use of drugs, and laws requiring the usage of seat belts in automobiles or helmets on bikes, are examples of paternalist laws. One of us has written elsewhere about why legal paternalism toward competent adults disrespectfully substitutes unjustified judgments for the target agent’s own judgment, regardless of any success it might have in motivating targets not to harm themselves (Glod 2013). He has also argued that paternalists face daunting informational constraints regardless of whether we should be concerned about autonomy as merely a capacity for self-direction (Glod 2015). The other of us has written against paternalism and in favor of harm to others being the only justification for laws (Cohen 2014). Here, we argue that legal paternalism involving incarceration for nonviolent drug crimes will largely fail to achieve its own objectives. We don’t consider—what also worries us—the unfortunate limits paternalism puts on autonomy. Along the way, we also treat non-paternalistic “social welfarist” arguments that justify incarceration in terms of preventing harm to others. We focus on drug addiction, as its criminal prosecution is a notable source of over-incarceration in the United States. 2 Our thesis is simple: we ought to have no criminal laws justified by paternalism; ridding our society of such laws would reduce the problem of over-incarceration, and paternalists and social welfarists should support their repeal.