The aim of my paper will be to assess the potentialities and limits opened by the Brexit and by the new European context after the election of French President Macron for the relaunch of the European Defence Policy. I will rely on the concept of strategic culture to show that even if many concrete initiatives can be identified (in the area of capabilities, armament or budget for instance via the mechanism of PESCO), the political contingent environment cannot completely change the recurrent diverging analysis of the strategic priorities of CSDP that can be found within the EU. If the retreat of the UK opened new possibilities to deepen European defense and make it evolve in the direction of a more important European strategic autonomy, it will not lift all the obstacles encountered by CSDP in the last decade. Thus the paper will confront the idea of path dependence induced by the weight of national strategic cultures with the evolutions made possible by the context of Brexit. Here the concept of strategic culture is particularly clarifying to understand that even if the UK used to exert a pressure to block some projects in CSDP like the project of setting up a European OHQ, the diverging strategic culture of the other EU member states, among which the two currently leading states in those matters, France and Germany, plays a major role to explain why CSDP does not manage to propose more collective solutions to fight terrorism for instance, or to address the issue of the Syrian conflict. And even the latest innovations such as the effective creation of a PESCO reflects the still quite diverging strategic priorities within the EU.