The subject-matter of this article is to consider relationship between liberty and security from a constitutional-democratic point of view. In recent years as terrorism becomes a world-wide and profound phenomenon, governments incline to overstep the reasonable limits of restricting civil liberties. In order to check this temptation on part of governments that subscribes to sacrifice liberty for state security we need a new perspective that gives priority to liberty. This, in turn, demands, in a constitutional-democratic regime, that in limiting liberties with genuine security concerns legislators and judges adopt "presumption of liberty" as the guiding principle along with proportionality.