We examine the conditions under which societal conflicts are peacefully processed by competitive elections when the contending parties can revert to force as an alternative. We show that the viability of the electoral mechanism depends on the balance of military force, the sharpness of divisions within a society, and institutions that moderate policies implemented by winners of elections. For elections to be held and their outcomes to be respected, the probabilities that they would be won by incumbents must bear an inverse relation to the magnitude of policy changes resulting from elections. Elections are competitive when their outcomes make some but not too much difference. Constraining the scope of policy divergence increases the range of the balance of force under which elections are competitive in divided, but not in homogeneous, societies. Hence, competitiveness of elections and constitutional constraints on policies – the norms being promoted as essential for democracies – do not always go together.