Does international law restrict the use of force by states in self-defense even when their survival is threatened? Should it? To answer these questions, I compare international law to domestic law and develop two ideal-types of emergency: in a ‘subject emergency’ law imposes absolute, justiciable limits on self-defense. In a ‘community emergency’ the sovereign, not law, determines what is necessary for the survival of the community and its legal system: sustaining the rule of law justifies its temporary retreat. I show that international law has elements of both ideal-types. It imposes some absolute limits on self-defense. However, international law also retreats, allowing the victim state to determine the (1) aims, (2) ad bellum proportionality, and (3) end of self-defense, as if armed threats triggered community emergencies. These three retreats serve the function of sustaining the rule of international law over the states at war. Retreats (1) and (3) also help sustain the rule of international law over the international community. That international law does and should not treat armed threats against states simply as subject emergencies, shows it can only sustain the rule of international law in an emergency by retreating. This is a negative litmus test for international law's ability to diffuse anarchy in International Relations.