From a discipline without a subject to a subject without a discipline.

This article suggests an approach to the classical issues of the public administration theory, through the so-called new institutionalism. It argues that public policies could be taken by public administration theory as a new object of study, which this theory has gradually lost in the past. Nevertheless, whether the policy sciences can be useful1 or not to develop public administration as a discipline depends on the theoretical bridge offered by the new institutional approach. To propose how and why is the main objective of this article, based on the Mexican academic debate.