Historians at one time emphasized the critical causal interventions of important individuals, ascribing decisive differences in outcomes across time and place to human agency and idiosyncratic initiative. Subsequently, structure, contingency, and a collection of nonidiosyncratic choices became more prominent in causal explanations. Culture, geography, climate, economic circumstance, ideology, etc., became the favored variables in attempts to answer significant questions about key turning points in the global past. In Why Nations Fail, however, Acemoglu and Robinson demonstrate that leadership and governance matter much more than we thought. Although structural analyses add powerfully to our research, it is the quality of leadership that often determines whether a state is to flourish politically or economically.