To be successful, the creation of the European Federation must be done in such a way that the new state will guarantee the former nations maximum flexibility and the widest possible scope for self-governance, i.e. that most decisions will be taken at the lowest possible level of governance. This would minimize the tensions stemming from cultural and social differences. The only way to do it could be through the process, which I call “cantonization of Europe”.
That is a reference to the way Switzerland has been governed for the last 200 years, giving maximum level of self-governance to each of its 26 cantons. That would effectively lead to the creation of the European Federation composed of former EU states, but in which some of the larger regions (say over 5m population) would have an automatic right to statehood, either on their own, or by merging with neighbouring regions of other states. To learn more, read here.