International law norms of the use of force, including the right of self – defence are probably the most controversial part of international law, despite calling them peremptory norms or norms of jus cogens. There are many risk and dangers which today represent a serious challenge to the international legal community. We are witnessing serious tendency to extend the cases when the armed use of force can be legally and morally justified. It is still open to the question which impact the military attacks on Afghanistan and Iraq will have on the development of international law, if the constraints on the right of self – defence are really removing, if “new doctrine” the use of force is relevant or if the concept of “responsibility to protect” or “to assist” represents an original contribution to strengthening international peace and security. In any case unilateral uses of armed force without authorization of the SC requires serious discussion. Substantial extension of the right of self - defence above the Art. 51 may lead to reappraisal of jus ad bellum and to removal of existing restrains on the right of self-defence within the UN collective security system and existing international law order. The tendency to enforce militarily protection of “human rights and democracy” against tyranny at international level is nowadays greater than ever. There is a large number of unilateral armed actions described as “preventive” or “pre - emptive” self-defence, humanitarian interventions or “anti - terrorist war”. It seems, however, that the extensive approach to the use of armed force does not bring expected results. In any case international law “reappraising the use of force” is at a crossroads.