A deterrence theory of punishment holds that the institution of criminal punishment is morally justified because it serves to deter crime. Because the fear of external sanction is an important incentive in crime deterrence, the deterrence theory is often associated with the idea of severe, disproportionate punishment. An objection to this theory holds that hope of escape renders even the severest punishment inapt and irrelevant. -/- This article revisits the concept of deterrence and defend a more plausible deterrence theory of (...) punishment—the wide-scope deterrence theory. The wide-scope theory holds that we must make the best use of all the deterrence tools available, including both external and internal sanctions. Drawing on insights from the early Confucian tradition, the article develops a deep deterrence theory, which holds that the most important deterrence tool involves internal, not external, sanction. It describes how internal sanctions deter potential offenses and why relevant policies need not conflict with liberalism’s respect for neutrality. (shrink)