This article casts light on the devices used in the struggle against post-2001 terrorism in Western democracies. It aims to show what is induced in the long term by the extension of those methods and by their institutionalization, as far as liberal values and Rule of law are concerned. It points out that emergency measures have become commonplace, which tends to establish a new norm in politics, both within the states as well as within the international system. From this point of view, the article argues that there is no radical opposition between the United States and European democracies on this question, despite what is commonly said. Europe keeps putting forward different approaches, but it has nonetheless submitted to the anti-terrorist dynamic and to its potential negative consequences.