This article examines one of the most pressing issues in contemporary constitutionalism: the dialectical tension between the imperative of national security and fundamental human rights guarantees in the face of the global threat of terrorism. It analyzes how the anti-terrorism agenda is becoming a catalyst for expanding state powers, which inevitably leads to restrictions on rights such as privacy, freedom of movement, and the privacy of correspondence. The author examines the key legal principles of “necessity in a democratic society” and “proportionality” as the primary tools for resolving this conflict. Based on an analysis of international and national legislation, the author concludes that the legitimacy and effectiveness of counterterrorism measures directly depend on the existence of effective mechanisms of oversight (judicial and parliamentary) over the activities of government bodies, preventing the security system from degenerating into a system of total oversight.