Justification and excuse are defenses used to argue that behavior that appears to be criminal is not illegal. Justification should be applied to conduct that is permissible rather than commendable. Many commentators have proposed a substantive theory of justification, but analysis points up serious deficiencies in their theory when it is applied to substantive problems in the criminal law. The liability of accessories is examined in light of the theories of justification and excuse, with the conclusion that it is also important to develop a theory of special relationships between accessories, principals, and potential victims. 124 footnotes.