Abstract
Strategic environmental assessment (SEA) literature has insistently drawn attention to the lack of a precise definition for SEA. This process of conceptual evolution continues, suggesting that it is hard to conceptually summarize the practice of SEA and that, at the same time, there is an urgent need to conceptualize it to give it a sense. The debate on a SEA definition is not just a theoretical matter: it has very relevant practical consequences for the SEA practice and its evaluation. The purpose of this article is to contribute to this debate by showing that behind the evolution of the SEA definition there is a discussion on the rationality of decision-making. According to that hypothesis, the evolution of the SEA definition could then be explained as an adjustment of the initial aim of SEA to the actual rationality realm of strategic decision-making. The clarification of the rationality of decision-making as a structuring element of the SEA definition is considered as the basis for a deliberative and institutional SEA definition.