In contrast to many influential accounts which assume that formal norms and national predispositions frustrate the development of shared security principles and commitments, contributions to this special issue of Études internationales suggest that an analysis of concrete practices underpinning csdp evidences the emergence of a genuine strategic culture. Thus, the aim of this essay is to put in relief and, simultaneously, investigate the different arguments structuring this outcome. While I emphasize the peculiarities of the articles examined, I argue that the evolution of csdp depends upon as much as it expresses three major features that enable the above pieces to hang together : first, the way in which the eu designs policies that are constitutive of its csdp ; second, the processes that the eu singles out ; third, the mechanisms through which its power is wielded.