It appears that in many countries Secret Intelligence Services (SIS) hold very powerful means to collect digital data; both in terms of quality and in terms of quantity. However, the activities of SIS are not governed by European law: According to article 4 no. 2 TFEU, national security remains the sole responsibility of each Member State. Accordingly, art. 72 TFEU stipulates that the chapter regarding the “area of freedom, security and justice” shall not affect the exercise of the responsibilities incumbent upon Member States with regard to the maintenance of law and order and the safeguarding of internal security. As a consequence, the legal situation regarding SIS may differ across the EU in the different Member States. One particular difference can be observed regarding the question whether SIS should have executive powers or not; while some countries follow an approach strictly distinguishing between law enforcement and SIS, some other countries offer their SIS at least limited executive powers. The latter might blur the lines between traditional law enforcement (for which the EU can have legislative competences, e.g. art. 82 TFEU) and the maintenance of national security.