Cyber security, like global warming or the coronavirus pandemic, is an international problem that requires an international solution. In the global domain of cyber space, individual nations are surprisingly limited in what they can do to defend against digital crime, espionage, terror and war. Technical expertise and professionalism are required, but strategic cyber security demands collaboration with allies. Today, the European Union (EU) and North Atlantic Treaty Organisation (NATO) leverage the combined power of dozens of governments and hundreds of first-class network security, law enforcement and intelligence agencies to share information, conduct investigations and publish attack attribution. Together, they build trust and isolate adversaries. Authoritarian regimes offer short-term help on cyber security that neglects economic development, democracy, the rule of law and human rights. The only credible cyber superpower is an international alliance whose military capacity is surpassed by that of its political, economic and social domains.