The United Nations faces an existential crisis. The norms that bind and ‘safeguard humanity’ are currently under threat. The deliberate bombing of hospitals and the indiscriminate killing of civilians has become almost routine in Syria and several other conflicts. Numerous governments and murderous non-state actors (like isis or Boko Haram) are defying international humanitarian and human rights law. This article argues that the solution to the current global exigency and a central challenge facing the next Secretary-General is to achieve an equilibrium shift away from crisis response and towards conflict prevention. This is especially true with regard to preventing mass atrocity crimes (genocide, war crimes, crimes against humanity and ethnic cleansing). Historically, no single issue has done more to tarnish the reputation of the un than the failure to halt atrocities. Under a committed Secretary-General, the un has unique capacity to prevent these crimes.