The EU was founded on the project of “Europe without borders”, which means elimination of internal borders between Member States according to Article 26 of the Treaty on the Functioning of the European Union. The counterpart of this objective has been the transfer of the controls to the external EU borders. In the Schengen area, external borders are controlled by common principles and procedures encompassed in the 2016 Schengen Borders Code. Member States have negotiated the Schengen agreement to maintain such external border controls, with the aim of protecting their citizens from various dangers and guaranteeing their national migration policies towards third-country nationals. Member States have therefore transposed the function of national border controls to the external EU borders. Cross-border cooperation within the EU has developed to reinforce the Schengen Space of free movement and has been jeopardized by the unorganized massive peak arrivals of migrants in 2015. This article analyses whether the 2015 Schengen crisis confirms the security-orientated approach or not, specifically as the crisis confronts the EU with national claims to recover the control of internal borders. It has been argued that this movement is proof of the resilience of Westphalian borders. This article is an attempt to show how European judicial power tried to limit such a national re-appropriation of borders, leading to a functional distinction between internal and external borders that may allow a departure from an exclusive security-orientated approach of external borders of the European Union towards a more cohesive approach to controls at EU external borders.