In the wake of 9/11 exceptionalism has gained in political leverage. Executive-centred government prevails in responses to 9/11; civil liberties have been curtailed; due process and fair trial can be ignored under particular circumstances; asylum and immigration procedures have been tightened; etc. What is at stake in these developments? In this essay I try to give an answer to this question by revisiting Franz L Neumann's concern that when fear of the enemy becomes the energetic principle of politics liberal democracy (...) is impossible. Revisiting the debates in legal and political theory in which he participated supports the view that security policy, in this case responses to terrorism cannot be evaluated only on the basis of how effective they are in dealing with a threat. In addition, a more political evaluation that looks at how security policies feed back into society is needed. Security responses can intensify the institutionalization of exceptionalism based on fear of the enemy. In that case security policy becomes paradoxical. It risks undermining liberal democracy through the very means by which it intends to save it. (shrink)