One of the challenges presented to democratization theory by the collapse of communist regimes is the need to take into account the impact of ethnonational diversity on the processes of transition. This article explores that question in a comparative analysis of the dissolutions of the multinational federations of Yugoslavia, Czechoslovakia, and the Soviet Union. It revisits what has been a core--although usually unarticulated--premise of the democratization literature: that the decisions and negotiations that critically shape regime transition occur in a single, central political arena, a political space common to all actors. In contrast to that perspective, the strategic political context for transition in multinational states differs both from that in homogeneous states and from that in unitary multinational states, in offering multiple arenas of political contestation. The implication for democratization in multinational states is that, depending on the institutional structure of the state, regime change may occur at different rates in different substate political arenas--the republics--in such a way as to trigger the erosion of central control over the transition. Where democratization theory has emphasized strategic choice conditioned by the balance of power between regime and opposition actors, an accounting of the politics of transition in ethnofederal states must emphasize (1) strategic choices by actors in multiple political arenas and (2) the shifting balance of power between center and republics.