This paper proceeds in three steps. First I review the theoretical debate within EU studies, showing that the study of leadership has developed in the past decade, but also that there is a major bifurcation in the literature between proponents of rational choice inspired principal-agent models and scholars who utilize similar models but replace the comprehensive rationality assumption with a more realistic bounded rationality assumption. This distinction between using the assumptions of full and bounded rationality has major implications for the theoretical expectations of the respective leadership theories, which will be expounded in section 2.

            Second, the paper then turns to an empirical analysis, showing that leadership has been a major factor in the history-making decisions of the past two decades. The section reviews findings on the leadership roles of EU institutions and governments; in particular looking at the Commission, EP, Council Secretariat, along with the Franco-German tandem and select Presidencies. The paper concludes by pointing towards new research on the conditions under which leadership is necessary, along with understudied empirical topics.