This document presents a review of the role played by the Security Council (S.C.) of the United Nations before those situations in which at an international level its involvement have been required, in what can be called “major cases of the use of armed force” from 1990. After a brief review of the relevant facts, the Article questions the legality of the of the (S.C.) statements after the disturbances to the international peace and security entailed by the situations of Iraq, Kosovo and Afghanistan, stressing the damage done to international law and the application of the United Nations Charter; this being a result of unilateral actions taken by countries or Organisations. Consequently, the essay ends highlighting the need to go back to the multilateral mechanisms to face contemporary threats to international peace and security.