This article examines the break-ups of post-communist Czechoslovakia and the Union of Serbia and Montenegro under consociationalism. According to Arend Lijphart, social divisions may be neutralized at the elite level with power-sharing mechanisms. Lijphart's theory has been abundantly criticized, particularly because, while its intention is to induce cooperation, consociationalism does not give leaders actual incentives to cooperate. Czechoslovakia and the Union qualified as consociations; however most favorable factors were absent. The states failed to overcome their divisions and broke apart. Both states were going through a democratization period, experienced differently in each republic. The article argues that the application of consociationalism at this time magnified the divisions. Stirring up the ethnic sensitivity of the population was the most reliable strategy for politicians to secure popular support. In this context, and with the EU enlargement prospect, the consociational structure, instead of bringing elites together, weakened the federal power and provided elites the opportunity to defend republican interests at the expense of the federations. Hence, while a consociation requires certain conditions and favorable factors, the context in which consociationalism is implemented, and particularly democratization periods, may have a decisive influence on the leaders’ ability to cooperate, on their decisions, and thereby on the state.