Deterrence in cyberspace is possible. But it requires an effort to develop a new domain-specific, conceptual, normative, and strategic framework. To be successful, cyber deterrence needs to shift from threatening to prevailing. I argue that by itself, deterrence is insufficient to ensure stability of cyberspace. An international regime of norms regulating state behaviour in cyberspace is necessary to complement cyber deterrence strategies and foster stability. Enforcing this regime requires an authority able to ensure States compliance with the norms at an (...) international level, run investigations into suspected State-run cyber operations to define attribution, expose breaches of the norms, and impose adequate sanctions and punishments. These requirements define a political mandate for an authority that will have a deep impact on international relations and geo-political equilibriums. The UN Security Council has the necessary resources and the political and coercive power to meet these requirements. The time has come to embrace this power to consolidate and enforce an international regime of norms to regulate state behaviour in cyberspace. Problems, mistakes, and even failures are to be expected, but they must not hinder the process. (shrink)