The contribution deals with the theme of “defensive bureaucracy” and its causes, with specific reference to the conflict between the lawmaker and jurisprudence. This conflict is in fact capable of orienting the decision-making choices, and the behavior of administrators and public officials, towards “defense” with respect to their criminal liability, and not also towards objectives of effectiveness and efficiency of administrative action. The crime of “abuso d’ufficio”, over time and in its different legislative and jurisprudential configuration, has always represented, and still represents, a paradigmatic case of this phenomenon: his analysis therefore represents a privileged point of view, to consider how the “defensive bureaucracy” is caused by the uncertainty of the regulatory and jurisprudential context, and how to deal with this problem