Coercive rules and their implementation are, in liberal democratic societies at least, subject to ethical constraints. The state's moral authority requires these constraints to be both cogent and effectively realised in doctrine. In short, the enterprise of subjecting individuals to coercive rules must be consistent with the delivery of criminal justice. Contemporary criminal theory is much exercised by the apparent contradictions and ambiguities characterising criminal law doctrine. Is this an inevitable part of the territory leading us to question the very possibility of criminal law delivering justice? Or, as the author prefers, is criminal justice an achievement in which one of the tasks of criminal theory is to set goals and identify deficiencies in a constant effort to improve the form and content of rules and procedures?