The article discusses the concept of national security and the problems generated by the political tensions between individual security and state security in the contemporary world. Even recognizing that the modern state is simultaneously a source of threats as well as a source of security to individuals, it seems that the very nature of the international system and national societies renders collective security incompatible with individual welfare. This requires us to live as best as we can with the inherent tensions of the concept of national security. To demonstrate that these tensions are real political problems and not just semantics, the article analyses the liberal tendency?based on legal positivism?to legally define situations in which governments could allege reasons of national security, as well as more recent tendencies to substitute the concept of national security with the notion of individual security. In conclusion, I provisionally adopt the perspective of the "theory of security complexes" as an alternative to the authoritarian, liberal and post-modern positions in the analysis of security matters.