In many cases, groups will choose to break away even when presented with a federal option. Even the best attempts to quell internal divisions based on diverging identities may not prevent people from creating their own states. Many people in Scotland, for example, are not happy with a federal alternative to independence. 
Far from creating harmony between conflicting ideas in large multi-ethnic blocks, federalism can exacerbate conflict. Federalism in the European Union has created endless gridlock. There are too many cultures rubbing shoulders and decision-making is slow or non-existent. Critics say that in the EU federalism will make decision-making impossible, as it has too many members with irreconcilable differences. Calls for European federalism has led to widespread discontent.
Granting autonomy in many places may be just as dangerous as enforcing the central government. In states such as Afghanistan where separatist movements are bolstered by outside influences, federalism has arguably increased the threat of violence.