We document that rules for leadership succession in ethnic societies that antedate the modern state predict contemporary political regimes; leadership selection by election in indigenous societies is associated with contemporary representative democracy. The basic association, however, is conditioned on the relative strength of the indigenous groups within a country; stronger groups seem to have been able to shape national regime trajectories, weaker groups do not. This finding extends and qualifies a substantive qualitative literature, which has found in local democratic institutions of medieval Europe a positive impulse towards the development of representative democracy. It shows that contemporary regimes are shaped not only by colonial history and European influence; indigenous history also matters. For practitioners, our findings suggest that external reformers' capacity for regime-building should not be exaggerated.