Theft, robbery, and default have robust attractions. Property and contract look fragile by comparison. On the whole and most of the time, they nevertheless prevail. This result borders on the counterintuitive, since it goes against palpable interests. Why is it that these interests nevertheless usually fail? It is far from self-evident that they should. An explanation is needed. The standard one is that property and contract prevail because the state enforces the laws that secure them. But unless cooperative behavior is for some reason first established, how can the state itself prevail?—since it is not obvious why it should. For it must stand up against the same robust, palpable interests as the very institutions it is supposed to protect, and must somewhere find the strength that property and contract need, but apparently cannot find in their own defense. Simply assuming that the state does uphold them, because after all this is what the facts are saying, is to my mind shallow, as well as potentially circular. Exploring the possibility of an endogenous theory may well permit a deeper insight into these institutions—even if the theory is no more than a coherent but counterfactual account of how they might have arisen, rather than a factual one of how they did arise.