Fragility arises when states are ineffective and when they are also illegitimate and unaccountable. These features are interconnected. People don’t want to cooperate with, or cede resources to, a state they cannot influence. We present a simple framework where the key to exiting fragility is a balance between the state and society. The state needs to develop more capacity, but to do this society needs to develop the ability to discipline and control it. We emphasize the existence of this type of “virtuous circle”—a phenomenon we call the “Red Queen effect.” We argue that the way of thinking about state-building is in terms of both widening the corridor in which the Red Queen effect operates and devising strategies to get into the corridor. We show how the framework helps account for the diminishing fragility of the state in post-apartheid South Africa, Somaliland, Sierra Leone, and Colombia.