Estonia’s success in averting a potential conflict over its Russian-speaking minority is often attributed to the intervention of the OSCE High Commissioner on National Minorities. Indeed, the Estonian case is one of the most satisfactory encounters in the period of Max van der Stoel’s impressive diplomatic engagement. However, deeper, structural factors were also important over the longer term. In particular, the voting system that Estonia adopted, based on the single transferable vote system of proportional representation, turned out to be important in encouraging political moderation. This article argues that a decisive factor in ethnic accommodation was the way the political system channelled the activities of the Russian-speaking groups into Estonian parties. Other contributory factors were the weakness of ethnic identity among the Russian-speakers and international constraints on Russian foreign policy. This analysis highlights the crucial role of domestic institutions in conflict prevention.